Assignment Role Lost


I have a process with several tasks (Task1 - Task2 …).

Normally when passing from Task1 to Task2 the role to witch Task2 is assigned to can change (the assignment is done on task is queued event).

Sometimes, but only sometimes (1%) Task2 is assigned to null (but it should not).

We have 6 clustered MWS servers, can this be a synchronization problem?

Has anyone encountered this issue before?