I switched to the new media library (at least according to the settings. It looks nearly identical after setting up the library so I'm not 100% sure. If it's meant to, well done on reproducing the look so well.), but it still occurs. One improvement is that clicking any item in the list seems to fix all of them at once now.
A couple of new small bugs seemed to show up once I changed over too:
When I imported my old library, my AC/DC tracks (and only those tracks) were missing the final letter on the artist and track tags, and other tags were blank. Clearing the library and scanning the folder to generate a new one fixed it.
If I highlight a track in the "songs" list, then select a different artist, that position in the list remains highlighted, unless there aren't that many tracks to show, which fixes it.
Also side note: I appreciate how responsive you are about feedback. It's a rarity.