Rule task started more than 100 000 times

We have a interesting problem.
We have process with rule tasks. The first task was started over 100 000 times (3 days loop).
I checked from logs, the process itself was started once, normally over REST API.
This first rule task depends on external service where there can be delays.
We don’t have circular dependencies.

How this can happen? Process is working asynchronously (using job-executor).
Same time other processes were started and processed well.
I created a unit test with same data and bpmn schema with timeouts and couldn’t repeat it.

Camunda, 7.9.0, Camunda Spring boot 3.0.0, Spring boot 2.0.2.RELEASE.

Any ideas would be appreciated,