Model element titles not rendered

[liamdennehy]

Simple model elements seem to only be displaying their definitions (in my example: def2, def3), while complex elements have their names rendered (def1, def4)
Simple model

The relevant div sections in the rendered HTML seem to be wrapped in this block:
<!---react-text: ###--->
Where '###' is a number

[webron]

Closing as duplicate of #2875.