I can only share a few tips:
1) If you have any kind of customisation of views at all (though I'm assuming you don't here), I recommend that you create a parallel run project that has only the generic views with no customisation - and revert to that one for debugging. (For
example, in custom views it is easy to accidentally obscure or omit some of the feedback information).
2) In this particular case:
- Are you editing a persistent object, or attempting to save a transient one? If the latter, then this kind of issue can arise if you have any associated transient objects that are not complete (or not saveable for other reasons). That said, you still
ought to be getting some kind of feeback about it.
- Are you using any complex types? (Though, again, more specific feedback should be there).
3) Sometimes it can be helpful to switch off the entity persistor and use the in-memory persistor to see if you get the errors with both - this is a one line change in the Run class.