Kilns that are repeatedly disabled and re-enabled by automation will eventually enter a weird state where they do the finish production animation repeatedly, but can't actually complete any job.
To fix this, either save+load or clearing the job and issuing it again is needed.
Steps to Reproduce
Set up a kiln with automation. Queue a job for it and fill it. While it is working, disable it and re-enable it a few times (5 should be enough), waiting 3 seconds between each state change. The kiln should now be bugged.
This issue has not been confirmed by a developer yet.