The problem occurs in the RAMJobStore on acquireNextTrigger() method. (I'm using org.quartz.SimpleTrigger)
the variable "timeTriggers" contains the "TriggerWrapper"(s). Those triggers have been put in the TreeSet "timeTriggers" when they were not executed yet. The treeSet use the compareTo(Object o) method from the org.quartz.Trigger object to sort the triggers. The method is based on the Date given by the getNextFireTime()
method.

The issue:
The method acquireNextTrigger() calls the method first() on timeTriggers, it give back a TriggerWrapper then the method remove is called, but if the trigger has executed the remove method will never find the TriggerWrapper in the TreeSet because the compareTo won't answer the same response.

If you need more info please tell me.