Premium Spotify in USA, using web player with Firefox.
Since the last few weeks, the web player makes annoying high-pitched beeps at random times. It happens once or twice during every song, at seemingly random times. Sometimes I'll get two within a few seconds. Other times they'll be five or ten minutes apart.
There is no control, remote or otherwise, going on. I just start an album or playlist, sit back and listen. There are no other devices showing up under the Spotify Connect button.
The beeps only start after playback is started, but after playback is stopped, they will continue as long as the Spotify browser session is open.
This makes listening to any music pretty much impossible.