Cool, restoring the old db should help get to the bottom of this. Each time you backup/restore the DAT file, if you could also capture a verbose log that would help with any subsequent debugging.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.