I have several jobs configured. The job "a" triggers on successful completion another bunch of jobs. Each job might also triggered independently via SCM changes and triggers also other jobs on completion. See the following picture which describes the hierarchy:

Since 1.609.1 I observe the following behavior. When job "a" finishes, the jobs "b", "c", "d,", "e", "f", "g" are triggered. "e" and "f" are executed without problems. But the jobs "b", "c", "d", "g" get stuck in the build queue forever. They are never executed. When I now remove job "g" from queue, "b", "c" and "d" are executed.

Threaddump where jobs are waiting in build queue and executer has nothing to do is attached.