I have a record of Shostakovich 11 identified in Roon, but it won’t show in the list of compositions. Here you can see it missing:
Here you can see that it does exist (navigated to album, then selected go to composition:
Not sure why this would be hidden in composition view.
In general I have found that Roon favors quantity over quality when it comes to data. Granted I have access to much more data with Roon than with just my tags, but the data is only about 90% right I’d say (which of course means its 10% wrong).