When attempting to filter tracks with a rule of is/is not in Track Collection, the list of options shown for the track collection is actually items from the Album Collections, resulting in 0 matches.
Plex Server Version 1.32.8.7639
Plexamp Version 4.9.5
Track collection
Album collection
Track collection selection
Only lists Album collections, which results in 0 matches:
Selecting album collection filter instead works as expected