I was able to replicate your issue when the rich-text field in question is also being used as a reference proxy - but not when it's just a lookup. This seems to be a bug in the new forms worth reporting.
In the interim to fix the immediate problem - you might consider adding a 'new' lookup copy of your rich text fields - and set it on the form so that when you're adding/editing the form you can use the dropdown reference proxy - but then on view just have the additional copy on the form. I didn't see the same behavior with showing tags when it was just a regular lookup, it seems isolated to just the reference proxy setup.
