Cache is LOCAL, eviction + passivation enabled. After put the entry gets passivated, shortly after an other thread tries to get() the entry, but get null.
Attached a log file. The key is "50b2c9e7-0a38-0043-01fc-76cdf49fa2ce". Tried JDBC and File store with same results, also sync/async store tested. It happens under some load.
I wasn't successful to create unit test for reproduction :-/