JCS never going out of the dispose methode

I have an application using many threads all calling JCS. When I close the application, the cache is usually working fine, but sometime, it stays stucked on the dispose methode.

The cacheEventQueue never going empty. Then it's looping on while ( keepGoing ) and never ending. I have to kill the application to exit.

It's difficult to reproduce. There is no fixed pattern so far.