Yep, I’ve noticed the exact same issue today. Thought the second speaker was blown but then I reversed the sequence of adding them to party up mode and now the other speaker got the same issues. UE need to work on their software I guess. PS: try to run a 60hz bass test track from Spotify or similar. You will hear the second speaker “popping” at this frequency. It happened to both of mine. One megaboom and one megaboom 3