If the timer fires at the same time as an update it results in the child being propagated twice. We need to synchronize to ensure that this does not happen. The update should cancel the timer, so it doesn't try and schedule a propagation.
Mark Proctor <email@example.com> updated the status of jira DROOLS-284 to Resolved
Fixed by Mark with this commit: https://github.com/droolsjbpm/drools/commit/859b1a5915fe89ba37483afc84c6dd00fe07878a
Verified on BRMS 6.0.0 ER5.