Stunner is setting <bpmn2:targetRef> of <bpmn2:intermediateCatchEvent> to <bpmn2:property id="> instead of <bpmn2:property name=""> at runtime, this leads to runtime errors where the engine cannot find the process variable and bombs out (19:02:52,909 ERROR [org.jbpm.runtime.manager.impl.error.ExecutionErrorHandlerImpl] (default task-36) Unexpected error during processing : java.lang.IllegalArgumentException: Could not find variable for event node)

The worst part of this is that if you clone the git repo down, fit the issue, and push it back, the resulting process will build and deploy, but stunner can no longer open it and leaves you with an xml editor. So at this point, there is no way to use stunner to create a process that uses signal events.