These errors thrown at unpredictable times and normal operation works just fine. So something odd going on. Perhaps a timing issue that can be glossed over.
Happens in EhCacheProvider.cfc at line 154:0:
152: arguments.objectKey = _fixObjectKeyCase( arguments.objectKey );
153: try {
154: return variables.cache.get( arguments.objectKey );
155: } catch( "java.lang.IllegalStateException" e ) {
156: // cache unavailable, probably due to shutdown
So perhaps we just need to catch any error here (and various other places throughout the provider).