Since last week I’ve had major issues with multi-room (10 devices across 6 rooms). I’m thinking this may be related to the newly added Apple Lossless support. I can get 3, maybe 4 rooms to play reliably, but adding 5 or 6 causes major issues with constant rolling dropouts, eventually leading to some speakers just silent (although the app thinks they are playing).
With Amazon Music, (which I don’t use, but tried it for testing), playback is stable.
I can also play to all rooms/devices reliably with Apple Music over Airplay - including adding 6 more “rooms” through airplay.
I have an Eero mesh network with excellent coverage, and I live in a rural setting so not a lot of interference from other networks.
Anyone having similar issues?