What version are you using?
The newer the version, the better the results with odd NZB's. I'd be using the current beta if I was you.
If you're using the latest beta, the NZB's Sonarr sends down as stored temporarily in the NZB's folder in the data folder. You could email some of the broken ones to
TS@Newsbin.comOdd NZB's work best if you feed them directly to the download list.