…in retrospect, maybe more of a design limitation with the zigbee protocols.
I had an interesting fault for the past day. My ND555 lost system automation - I could control the streamer through the app and the remote (next track, previous track, pause, sleep etc), but wasn’t able to adjust the volume (volume up/down, or mute) through the app or remote. I’ve got system automation enabled to my 552, which has been running without fault as long as I’ve had a 555 (and the NDX2 before it).
It turns out that a faulty apple tv (gen2 4K) remote (it constantly did a “volume up on the TV” command) might have been the problem - when I disabled the apple TV remote, the fault disappeared.
My assumption is that the apple tv (which uses bluetooth) might have been jamming the frequencies used for the Naim remote. It doesn’t explain the app behaviour (unless the app also uses bluetooth to communicate with the streamer for volume purposes…)