SPEC: If a component is called and the JTA transaction is propagated into that component:
If there is a persistence context of type SynchronizationType.UNSYNCHRONIZED
associated with the JTA transaction and the target component specifies a persistence context of type SynchronizationType.SYNCHRONIZED, the IllegalStateException is thrown by the container

We have a stateful session bean (SFB1) / PC: TRANSACTION/UNSYNCHRONIZED)
stateful session bean (SFB2) / PC: TRANSACTION/SYNCHRONIZED)

SFB1 method M1 (REQUIRED) calls SFB2 Method 2 (REQUIRED):
PC is propagated from SFB1 to SFB2 without any exception.