I’m sure someone will confirm, but my thoughts: 

Is the group offered as a target to play to when you are offered Airplay devices, or just  single speakers? If you only select a single speaker, that seems to me to be expected, logical behaviour. 

It’s just a single speaker. Not all speakers in the group are AirPlay ready. However, with the old app, it was possible to target a single speaker via AirPlay and keep the group intact. Also, the AirPlay sound plays on all speakers, once I re-add the lost speakers to the group.

Hi @Allie Gator 

Welcome to the Sonos Community!

Grouping non-AirPlay compatible speakers in with an AirPlay feed is not yet possible with the new Sonos app, but this feature will be returning at some point soon.

Or, so my documentation says, but you say:

If this is the case, then things are already better for you than we would expect. If this works, please continue doing this, and at some point, the non-AirPlay speakers will just stop dropping off the group (once an update that fixes it is in place).

In short, it’s us, not you, and we are working on it.

I hope this helps.

Hi — OK, thanks! Fingers crossed it will be resolved soon.