This is strange. I checked again and reverted the the PersistentIdentifierBag myself. For me, this leads to three failed tests:

• PersistentIdBagTest.testDeleteViaIterator
• PersistentIdBagTest.testDeleteViaListIteratorNext
• PersistentIdBagTest.testDeleteViaListIteratorPrevious

I executed the tests from the IDE (IntelliJ), I don't know if it makes any difference if they are executed via gradle (unfortunately I am not so familiar with gradle).

Find the logs of the failed (failed_tests.log) and successful (successful_tests.log) attached, hope that helps. If you have any further questions, let me know.