I just did a large amount of FLAC metadata editing (~1k files) using “TagScanner”.
After doing a “Start Full Scan” from the web interface, these changes were not visible in iTunes. I restarted mt-daapd, the changes had still not applied.
I removed the database, and had mt-daapd re-create it from scratch. The metadata updates I made were now visible in iTunes.
I am not sure if this is the correct behavior, but if it is I would like to request a “Full Reload” button on the web interface that rebuilds the database from scratch, instead of re-scannnig.