Same here. When I click on the heart sign on a local tracks, the heart sign goes solid. However, if I visit some other album and go back, the heart sign is back to hollow. Ie, the favorite setting does not stick.
In a Qobuz track, when I click on the plus sign, the spinning circle goes on for a few seconds and then the plus sign returns. Nothing registers.
I rebooted the Pulsar to try the same thing. Now the favorite setting sticks on local tracks. However, after I left the pulsar on overnight, the next day, the favorite setting no longer sticks. This seems to be a new bug in Sense 3.1.0. I never turn off my pulsar previously, and had no problem with favorites.