Some custom fields were deleted in JIRA but there were still in the behaviour-plugin. At the beginning, the behaviour was mapped to all issue types. If the behaviour mapping is changed, the indexing fails and the logs indicate that the deleted fields cannot be found. This is the error log i get:
[onresolve.jira.groovy.Behaviour] Could not find field with key: customfield_10002
As a troubleshoot, I tried to delete the fields in the behaviour plugin as well but it did not help. The JIRA version is v6.1.4#6159-sha1:44eaede. The behaviour plugin version is 0.5.10. The script runner version is 2.1.16.