incorrect unit of work when using association class

[wickedOne]

Bug Report

Q	A
BC Break	no
Version	2.17.x

Summary

the unit of work appearss "polluted" after persist -> flush -> clear -> find -> remove -> flush routine

Current behavior

when a parent class has a child collection using an association class, the unit of work contains proxy classes after removal of the entities when the entity manager is cleared in between persisting and removing. nevertheless, these entities are no longer present in the database

How to reproduce

check the code in this POC to reproduce

Expected behavior

expected behaviour would be the proxy classes not to be present in the unit of work after the second flush