Interrupting event subprocess is activated more than once

[saig0]

Describe the bug

I deployed a BPMN process with an embedded subprocess. The subprocess contains a non-interrupting and an interrupting event subprocess. The non-interrupting event subprocess is triggered and still active.

Now, the interrupting event subprocess is triggered once and gets activated. But it is activated more than once!
This can lead to expected behavior because the tasks may be processed multiple times.

It seems that the number of created instances of the interrupting event subprocess depends on the number of active instances of the non-interrupting event subprocess. If no instance is active (anymore) then it creates only once of the interrupting event subprocess.

The same behavior is observed if the embedded subprocess has more than one active element instance (e.g. a parallel gateway with two active tasks).

To Reproduce

1. deploy the BPMN process event-scope-test-reduced-3.bpmn.txt

./bin/zbctl deploy ~/Downloads/event-scope-test-reduced-3.bpmn

2. create a new process instance

./bin/zbctl create instance event-scope-test --variables='{"key":"key-1"}'

3. trigger the interrupting event subprocess by publishing a message

./bin/zbctl publish message m2 --correlationKey="key-1"

4. verify that the interrupting event subprocess is activated twice

Expected behavior

The interrupting event subprocess is activated only once.

The BPMN spec says that interrupting event subprocesses can be activated only once because it interrupts the event scope of the event subprocess.

Log/Stacktrace

None.

Environment:

• OS: Camunda Cloud
• Zeebe Version: 8.0.0
• Configuration: