FYI - Ran into this too.
It was a pretty big pain in the butt.
The DB validation would kick in and kill the request, but the in memory would not.
The weird thing is. it would generate the Primary Keys and everything, and look like it was working fine in memory.
It just died when it tried to persist to the DB level.
No errors, nothing… ever.
It didn’t error because the persisting seemed to happen after the page was processed.