We have found some suspicious behaviours of the engine when we set AsyncMode to true (https://issues.jboss.org/browse/JBPM-5880). Problems are (see attached reproducers):

Process ProbAsync:

1. Timer "timer 1" is never triggered.

2. When we try to signal the subprocess the following exception is thrown:

Unable to complete your request. The following exception occurred: "Unexpected error during processing: org.jbpm.workflow.instance.node.AsyncEventNodeInstance cannot be cast to org.jbpm.workflow.instance.node.EventSubProcessNodeInstance"

3. After completing the human tasks there is a problem in the Event based gateway. In every operation, even trying to abort, the exception is:

Unexpected error during processing Could not find node instance when deserializing exclusive group instance: 8: java.lang.IllegalArgumentException: Could not find node instance when deserializing exclusive group instance: 8

Process AsyncParallel

1. Process never ends.