A process instance doesn't complete after taking an incoming flows twice at an inclusive gateway

[saig0]

Describe the bug

I have the following process with an inclusive gateway that joins two paths:

Given:

• The task A is active
• The task B is active

When:

• The non-interrupting message boundary event of task B is triggered
• The task B is completed
• The task A is completed

Then:

• The process instance activated and completes the inclusive gateway
• The process instance reaches the end event
• The process instance is still active but without any active BPMN element

Note:

• If task A is completed first then the inclusive gateway and task C are activated/completed twice. The process instance completes after reaching the end event, as expected.

To Reproduce

1. Deploy the following process inclusive-gateway-with-exclusive-gateway.bpmn
2. Publish a message with the name M1 and the correlation-key "key"
3. Complete the job B of the task B
4. Complete the job A of the task A
5. Verify that the process instance reaches task C and the end event
6. Verify that the process instance is not completed

Expected behavior

The process instance is completed after reaching the end event.

How often should the inclusive gateway be completed?

• From Camunda 7: once. The documentation mentions this behavior as a Camunda-specific behavior (ref).
• From the BPMN specification: twice. The sequence flow S2 is taken twice. When the sequence flow S1 is taken, the inclusive gateway completes because all incoming sequence flows are taken. The gateway consumes one token per sequence flow and produces one token for the outgoing sequence flow. There is one token left on the gateway. Since no other token can reach the gateway, the gateway completes, consumes the token, and produces another token for the outgoing sequence flow.

Log/Stacktrace

Environment:

• OS:
• Zeebe Version: 8.6.0-SNAPSHOT
• Configuration: