Hi,
My advice to help you diagnose;
Turn exclusive flags back on for your parallel asynchronous executions as this will remove a potential source of optimistic locking exceptions.
Consider your remote service calls, are you using the connector library? Sockets based on the connector library may be held in a blocked state for a long time. This can cause undersirable side effects in the job executors…
Consider this thread (and others) to more agressively timeout. This thread regarding JSoup may also be of interest…
regards
Rob