@mpomerantz I've experienced the same occasionally. Is this happening when the music is streamed files vs. local file on a drive/NAS? If the latter case, one thing that helped was in Roon Settings>Library>Skipped Files you can see a list of tracks that Roon is having trouble digesting. These may include corrupt tracks, incompatible file formats, png artwork. I found that removing those tracks from my library folder helped eliminate the issue.
If they are all streamed files, all I can suggest is make sure you have latest updates in Roon, Sonictransporter and the OS on your remotes.
If none of that helps, a deletion/reinstall of Roon database and Core might help, but that will take some time. PM if you need help with this. I crawled up the learning curve and did so to fix another issue.
Cheers,
Spencer