Just ran into this issue over the weekend on a user database (ID 16). We're running SQL Server 2012 (11.0.3128)

Fairly comfortable that we don't have corruption as I have run the DBCC CHECKDB and no issues are returned.

Given that Microsoft have released a patch for this when it occurs in tempdb, I'm going to put this one down to the extensive use of NOLOCK hints used by our developers in the application code.

I may finally have something more than "Your queries will return inconsistent results." to beat the developers over the head with!