Guessing that site is suspect then, first time using it, my apologies about that. I unfortunately only have the normal logs and I have looked through them, there is nothing that I can spot that would cause this strange behaviour, only thing I could spot is the SceneMappingService kicked off an update and the RssSyncService started a RSS Sync while the ParsingService was still busy, however I doubt it’s that causing the problems (Happy to send them along if they can help). Would I have to run NzbDrone from the console if I wanted to enable the trace logs?
I have uploaded the detailed trace logs to http://sdrv.ms/1bpFUZ1 after managing to reproduce the problem. It matched “Air Crash Investigation - Mayday - 2x03 - Killing Machine (Hijacked)” to “Food.And.Drink.2013.S02E03.HDTV.x264-C4TV” as can be seen in the logs. I see when the search happens NZB MEgasearcH is returning 600 items and very few of them are matching “Air Crash Investigation - Mayday - 2x03 - Killing Machine (Hijacked)” how ever I would assume NzbDrone will not just blindly accept results returned as being correct.