Return value of Cache.remove(key) not consistent in transactional context

I have a scenario where multiple threads attempt to remove the same key concurrently via "cache.remove(key)" (each thread having explicitly started a transaction).
I expect only one thread to succeed, ie. only one invocation of "cache.remove(key)" to return a non-null value.
But that is not the case, the return value of "cache.remove(key)" is non-null for more than one thread.

In that sense, "cache.remove(key)" seems to behave differently from "cache.remove(key, value)".

The bug can be reproduced by using a test analogous to the one in "DummyTxTest" (ISPN-2077), but using "cache.remove(key)" instead of "cache.remove(key, value)".