Parallel to the Bluetooth lag issue (Bluetooth audio lag after firmware update - #43 by PhilippVH) with Qb2 FW 4.3.0.6408, I noticed that the play/pause soft button on the top dial does not work anymore, neither in Internet radio, nor when streaming Qobuz or from a local NAS. The skip forward and backward button (to the left and right of play/pause) don’t work either. They flicker shortly when pressed, but nothing happens. One has to use the app to control playback. I’ve rebooted several times.
Before you do a factory reset, the prior thing to try is a simple power off restart of your Qb2. Unplug it from the mains for half a minute or so then plug it in and turn it on.
A strange thing about the factory reset: it doesn’t seem to clear the login credentials for Qobuz. At least I hadn’t to re-enter them after the reset and still can stream. So, one should consider logging out of the service explicitly when selling a Qb2.