Rule with Jira Connector cannot find parent issue


I have a couple of rules using a Jira connector and create subtasks in Jira.

This works fine, but now, I cannot update the rules, because I get an error, that the parent issue cannot be found.
The rules still create new subtasks in Jira to this parent issue. Also, I can see a lot of tasks from the project in Jira when searching from Kibana, so I assume, it is no security issue.

That parent issue by now has many subtasks and opens quite slow in Jira itself, so my question is, if there is a timeout in Kibana when searching for the parent issue and this could be the problem in Kibana.

Any ideas?

Thanks and best regards,