diff --git a/src/traces/scattergl/index.js b/src/traces/scattergl/index.js
index 8831fdb6bdb..63a0a03dcbf 100644
--- a/src/traces/scattergl/index.js
+++ b/src/traces/scattergl/index.js
@@ -395,18 +395,17 @@ function plot(gd, subplot, cdata) {
             scene.line2d.update(scene.lineOptions);
             scene.lineOptions = scene.lineOptions.map(function(lineOptions) {
                 if(lineOptions && lineOptions.positions) {
-                    var pos = [], srcPos = lineOptions.positions;
+                    var srcPos = lineOptions.positions;
 
                     var firstptdef = 0;
-                    while(isNaN(srcPos[firstptdef]) || isNaN(srcPos[firstptdef + 1])) {
+                    while(firstptdef < srcPos.length && (isNaN(srcPos[firstptdef]) || isNaN(srcPos[firstptdef + 1]))) {
                         firstptdef += 2;
                     }
                     var lastptdef = srcPos.length - 2;
-                    while(isNaN(srcPos[lastptdef]) || isNaN(srcPos[lastptdef + 1])) {
-                        lastptdef += -2;
+                    while(lastptdef > firstptdef && (isNaN(srcPos[lastptdef]) || isNaN(srcPos[lastptdef + 1]))) {
+                        lastptdef -= 2;
                     }
-                    pos = pos.concat(srcPos.slice(firstptdef, lastptdef + 2));
-                    lineOptions.positions = pos;
+                    lineOptions.positions = srcPos.slice(firstptdef, lastptdef + 2);
                 }
                 return lineOptions;
             });
@@ -437,36 +436,38 @@ function plot(gd, subplot, cdata) {
                 if(trace._nexttrace) fillData.push(i + 1);
                 if(fillData.length) scene.fillOrder[i] = fillData;
 
-                var pos = [], srcPos = (lineOptions && lineOptions.positions) || stash.positions;
+                var pos = [];
+                var srcPos = (lineOptions && lineOptions.positions) || stash.positions;
+                var firstptdef, lastptdef;
 
                 if(trace.fill === 'tozeroy') {
-                    var firstpdef = 0;
-                    while(isNaN(srcPos[firstpdef + 1])) {
-                        firstpdef += 2;
+                    firstptdef = 0;
+                    while(firstptdef < srcPos.length && isNaN(srcPos[firstptdef + 1])) {
+                        firstptdef += 2;
                     }
-                    var lastpdef = srcPos.length - 2;
-                    while(isNaN(srcPos[lastpdef + 1])) {
-                        lastpdef += -2;
+                    lastptdef = srcPos.length - 2;
+                    while(lastptdef > firstptdef && isNaN(srcPos[lastptdef + 1])) {
+                        lastptdef -= 2;
                     }
-                    if(srcPos[firstpdef + 1] !== 0) {
-                        pos = [ srcPos[firstpdef], 0 ];
+                    if(srcPos[firstptdef + 1] !== 0) {
+                        pos = [srcPos[firstptdef], 0];
                     }
-                    pos = pos.concat(srcPos.slice(firstpdef, lastpdef + 2));
-                    if(srcPos[lastpdef + 1] !== 0) {
-                        pos = pos.concat([ srcPos[lastpdef], 0 ]);
+                    pos = pos.concat(srcPos.slice(firstptdef, lastptdef + 2));
+                    if(srcPos[lastptdef + 1] !== 0) {
+                        pos = pos.concat([srcPos[lastptdef], 0]);
                     }
                 }
                 else if(trace.fill === 'tozerox') {
-                    var firstptdef = 0;
-                    while(isNaN(srcPos[firstptdef])) {
+                    firstptdef = 0;
+                    while(firstptdef < srcPos.length && isNaN(srcPos[firstptdef])) {
                         firstptdef += 2;
                     }
-                    var lastptdef = srcPos.length - 2;
-                    while(isNaN(srcPos[lastptdef])) {
-                        lastptdef += -2;
+                    lastptdef = srcPos.length - 2;
+                    while(lastptdef > firstptdef && isNaN(srcPos[lastptdef])) {
+                        lastptdef -= 2;
                     }
                     if(srcPos[firstptdef] !== 0) {
-                        pos = [ 0, srcPos[firstptdef + 1] ];
+                        pos = [0, srcPos[firstptdef + 1]];
                     }
                     pos = pos.concat(srcPos.slice(firstptdef, lastptdef + 2));
                     if(srcPos[lastptdef] !== 0) {
diff --git a/test/jasmine/tests/config_test.js b/test/jasmine/tests/config_test.js
index dd6ce559ca0..7054a849f88 100644
--- a/test/jasmine/tests/config_test.js
+++ b/test/jasmine/tests/config_test.js
@@ -608,14 +608,14 @@ describe('config argument', function() {
             gd = parent.childNodes[0];
         }
 
-        it('should resize when the viewport width/height changes', function(done) {
+        it('@flaky should resize when the viewport width/height changes', function(done) {
             fillParent(1, 1);
             Plotly.plot(gd, data, {}, {responsive: true})
             .then(testResponsive)
             .then(done);
         });
 
-        it('should still be responsive if the plot is edited', function(done) {
+        it('@flaky should still be responsive if the plot is edited', function(done) {
             fillParent(1, 1);
             Plotly.plot(gd, data, {}, {responsive: true})
             .then(function() {return Plotly.restyle(gd, 'y[0]', data[0].y[0] + 2);})
@@ -623,7 +623,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should still be responsive if the plot is purged and replotted', function(done) {
+        it('@flaky should still be responsive if the plot is purged and replotted', function(done) {
             fillParent(1, 1);
             Plotly.plot(gd, data, {}, {responsive: true})
             .then(function() {return Plotly.newPlot(gd, data, {}, {responsive: true});})
@@ -631,7 +631,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should only have one resize handler when plotted more than once', function(done) {
+        it('@flaky should only have one resize handler when plotted more than once', function(done) {
             fillParent(1, 1);
             var cntWindowResize = 0;
             window.addEventListener('resize', function() {cntWindowResize++;});
@@ -650,7 +650,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should become responsive if configured as such via Plotly.react', function(done) {
+        it('@flaky should become responsive if configured as such via Plotly.react', function(done) {
             fillParent(1, 1);
             Plotly.plot(gd, data, {}, {responsive: false})
             .then(function() {return Plotly.react(gd, data, {}, {responsive: true});})
@@ -658,7 +658,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should stop being responsive if configured as such via Plotly.react', function(done) {
+        it('@flaky should stop being responsive if configured as such via Plotly.react', function(done) {
             fillParent(1, 1);
             Plotly.plot(gd, data, {}, {responsive: true})
             // Check initial size
@@ -676,7 +676,7 @@ describe('config argument', function() {
         });
 
         // Testing fancier CSS layouts
-        it('should resize horizontally in a flexbox when responsive: true', function(done) {
+        it('@flaky should resize horizontally in a flexbox when responsive: true', function(done) {
             parent.style.display = 'flex';
             parent.style.flexDirection = 'row';
             fillParent(1, 2, function() {
@@ -688,7 +688,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should resize vertically in a flexbox when responsive: true', function(done) {
+        it('@flaky should resize vertically in a flexbox when responsive: true', function(done) {
             parent.style.display = 'flex';
             parent.style.flexDirection = 'column';
             fillParent(2, 1, function() {
@@ -700,7 +700,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should resize in both direction in a grid when responsive: true', function(done) {
+        it('@flaky should resize in both direction in a grid when responsive: true', function(done) {
             var numCols = 2, numRows = 2;
             parent.style.display = 'grid';
             parent.style.gridTemplateColumns = 'repeat(' + numCols + ', 1fr)';
@@ -712,7 +712,7 @@ describe('config argument', function() {
             .then(done);
         });
 
-        it('should provide a fixed non-zero width/height when autosize/responsive: true and container\' size is zero', function(done) {
+        it('@flaky should provide a fixed non-zero width/height when autosize/responsive: true and container\' size is zero', function(done) {
             fillParent(1, 1, function() {
                 this.style.display = 'inline-block';
                 this.style.width = null;
@@ -740,7 +740,7 @@ describe('config argument', function() {
 
         // The following test is to guarantee we're not breaking the existing (although maybe not ideal) behaviour.
         // In a future version, one may prefer responsive/autosize:true winning over an explicit width/height when embedded in a webpage.
-        it('should use the explicitly provided width/height even if autosize/responsive:true', function(done) {
+        it('@flaky should use the explicitly provided width/height even if autosize/responsive:true', function(done) {
             fillParent(1, 1, function() {
                 this.style.width = '1000px';
                 this.style.height = '500px';
diff --git a/test/jasmine/tests/gl2d_plot_interact_test.js b/test/jasmine/tests/gl2d_plot_interact_test.js
index e80d9606352..342b7cbc280 100644
--- a/test/jasmine/tests/gl2d_plot_interact_test.js
+++ b/test/jasmine/tests/gl2d_plot_interact_test.js
@@ -1186,6 +1186,79 @@ describe('Test gl2d plots', function() {
         .catch(failTest)
         .then(done);
     });
+
+    it('@gl should not cause infinite loops when coordinate arrays start/end with NaN', function(done) {
+        function _assertPositions(msg, cont, exp) {
+            var pos = gd._fullLayout._plots.xy._scene[cont]
+                .map(function(opt) { return opt.positions; });
+            expect(pos).toBeCloseTo2DArray(exp, 2, msg);
+        }
+
+        Plotly.plot(gd, [{
+            type: 'scattergl',
+            mode: 'lines',
+            x: [1, 2, 3],
+            y: [null, null, null]
+        }, {
+            type: 'scattergl',
+            mode: 'lines',
+            x: [1, 2, 3],
+            y: [1, 2, null]
+        }, {
+            type: 'scattergl',
+            mode: 'lines',
+            x: [null, 2, 3],
+            y: [1, 2, 3]
+        }, {
+            type: 'scattergl',
+            mode: 'lines',
+            x: [null, null, null],
+            y: [1, 2, 3]
+        }, {
+        }])
+        .then(function() {
+            _assertPositions('base', 'lineOptions', [
+                [],
+                [1, 1, 2, 2],
+                [2, 2, 3, 3],
+                []
+            ]);
+
+            return Plotly.restyle(gd, 'fill', 'tozerox');
+        })
+        .then(function() {
+            _assertPositions('tozerox', 'lineOptions', [
+                [],
+                [1, 1, 2, 2],
+                [2, 2, 3, 3],
+                []
+            ]);
+            _assertPositions('tozerox', 'fillOptions', [
+                [0, undefined, 0, undefined],
+                [0, 1, 1, 1, 2, 2, 0, 2],
+                [0, 2, 2, 2, 3, 3, 0, 3],
+                [0, undefined, 0, undefined]
+            ]);
+
+            return Plotly.restyle(gd, 'fill', 'tozeroy');
+        })
+        .then(function() {
+            _assertPositions('tozeroy', 'lineOptions', [
+                [],
+                [1, 1, 2, 2],
+                [2, 2, 3, 3],
+                []
+            ]);
+            _assertPositions('tozeroy', 'fillOptions', [
+                [undefined, 0, undefined, 0],
+                [1, 0, 1, 1, 2, 2, 2, 0],
+                [2, 0, 2, 2, 3, 3, 3, 0],
+                [undefined, 0, undefined, 0]
+            ]);
+        })
+        .catch(failTest)
+        .then(done);
+    });
 });
 
 describe('Test scattergl autorange:', function() {