If a builder becomes disabled, but has active tasks, the scheduler does not take any action. Furthermore, this situation prevents the scheduler from timing out the assignment.
This was observed in the CentOS cbs koji instance earlier this week.
Fix forthcoming
Metadata Update from @mikem: - Custom field Size adjusted to None
Metadata Update from @mikem: - Issue set to the milestone: 1.36
Metadata Update from @mikem: - Issue tagged with: testing-custom
Metadata Update from @mfilip: - Issue tagged with: testing-done
Commit b66ff6c6 fixes this issue
Commit 370b1ff0 fixes this issue
Metadata Update from @tkopecek: - Issue tagged with: scheduler
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/4504
Please continue any further discussion there.