Did you check for blocking? Did you check what wait type the query is getting? Did you check for any messages in the error log?
It probably isn't a stats issue if the query plan can't be generated, but that doesn't mean it's a bug unless you've rules out every single other possibility (and there are lots)
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability