This is a regression from H4.

1. EntityVerifyVersionProcess#doBeforeTransactionCompletion throws OptimisticLockException

2. ActionQueue.BeforeTransactionCompletionProcessQueue#beforeTransactionCompletion re-throws it

3. JtaTransactionCoordinatorImpl#beforeCompletion calls physicalTransactionDelegate.markRollbackOnly()

There is nothing in the log and the exception is gone. All you get is a rolled back transaction.

(I've noticed this new behavior in other cases as well but at least with a SQLExceptionHelperManagerUtilSpringSpringSpringFactory thing logging e.g. a ConstraintViolationException. Logging and throwing exceptions problematic in production, of course.)