AAF produces error upon opening, show stopper

We are on the middle of major movie project and suddenly following bug has appeared on our workflow. Upon creating AAF with filtered sub-roles and opening it on Pro Tools, we are now getting always the following error at the end of AAF import.

"Could not complete your request because Assertion in "/Volumes/Development/194038/ProTools/NewFileLibs/FF/Audio/FF_AudioFile.cpp", line 1100."

The result is a session that can't be used as that same error is always shown upon opening the session. We have tried importing the AAF on PT 11.x HD, 12.7 HD and 12.7 on two separate systems and they all behave the same way.

If we don't filter any sub-roles everything is fine, but the second at least one sub role is omitted, the error appears.

I can send our simple test example of fcpxml and AAF's with sub roles filtered (error) and all sub roles included (no error) if needed.

We are stuck at the moment delivering meaningful AAF's to audio post.