Many Albums ending up in [untagged] group

[feeling_zenjp]

Thanks for the response.

My collection comprises of about 600 ripped CDs all with the metadata supplied using dbpoweramp ID3 batch converter. The rest are download purchases. In the case of the example provided, both the albums are download purchases. However, the ID3 tags were again supplied by dbpoweramp.

So in this case, the problem singles one out but not the other and the tags are both supplied by the same tool.

As requested, I set the StartupScan property to "full" and rescanned the library on trace level, using just the artist directory to reduce noise so the attached file contains a scan for one album that works and one album that remains classified as "untagged" after dumping and reloading the control point cache directly from Minimserver.