I seem to have a problem of the feed importers not unlocking.
My importers run on cron to import videos from youtube to create a video content type. I am using feeds crawler and youtube parser.
After cron has run, the importer works fine and video nodes are created as expected, but the importers is then still locked, so will not import again until I have manually unlocked it.
No errors are reported in the log.

Can someone give me a clue as to what I am doing wrong or where to start looking for the problem?
Thanks