An signal sent by a subprocess is not captured correctly in an intermediate capture event.

To detect, you can set the scope to project instead of per process and previous instances of the project will capture the signal (as at that time they have the listener waiting for the signal)

Attached a project with signal scope "Project" and output showing that the previous instance listen to this signals

solution

To avoid problems with the action nodes (intermediate throw) I added a new metadata for the node
"executeActionAfterComplete" when is set to true the signal is process after finishing processing the current flow.(like a passthrough)

https://github.com/kiegroup/jbpm/pull/1880/files#diff-3bb9f48c4484a807e42314ab3250ad0f97819113aadac6739c9bc771a536777aR77-R79