[Flow] Can't update abstract models anymore

[Steffen Wickham]

Hello list,

I'd discovered some strange behaviour on Flow after the latest
dev-master update, maybe it's a local issue but had someone else
discovered the same problem already?
I've got a model called "RefereeAssignment" which derives from the base
class "AbstractAssignment". Adding and deleting items to or from the
Repository works fine for me. But surprisingly I can't update items
through the Repository which is a mandatory feature. :,(

Not only this model is affected. My match types ("Match" is derived from
"AbstractMatch") and even my Party Model ("Referee" is derived from
\TYPO3\Party\Domain\Model\AbstractParty) can't be updated through its
Repositories as well.
I'd tried to catch Exceptions while calling update(), but no Exceptions
thrown...

Does anyone can reproduce the same error? If there is someone I will
open a issue on forge.
Does anyone has a hint to investigate this issue more deeply?

Greetings
Steffen