@Crash67,

Did the Sonos system actually disconnect, or was it just a device multicasting ‘discovery’ issue by the controller App(s)?

I don’t personally use eero, but the usual thing for a wireless ‘mesh’ setup and Sonos, is to run all hubs in Wireless AP ‘bridged’ mode, rather than having the mesh system setup in ‘router’ mode, with a ‘bridged’ router (which is often ISP provided in most cases).

It’s suggested as best practice to disable the wireless adapters on the router, then simply wire a single standalone Sonos device (not a HT surround, or sub) direct to the main router and placed 1 metre away from any other wireless AP, or other wireless device.

It’s also helpful (albeit optional) to reserve the Sonos addresses in the DHCP reservation table and set the SonosNet channel to one that is not in use by the mesh hubs (I personally recommend doing those things).

So it perhaps might depend if you were originally following that ‘typical’ suggested setup mentioned above, or it might just be the case that the recent eero update caused the router to perhaps have some difficulty re-assigning IP addresses arising in some duplicate addressing etc. which I guess can happen if multiple devices are simultaneously updated and/or rebooted together and the local DHCP server gets itself in a bit of a muddle (er…perhaps?)

Thanks for reply @Ken_Griffiths .  

1.  >>>usual thing for a wireless ‘mesh’ setup and Sonos, is to run all hubs in Wireless AP ‘bridged’ mode, rather than having the mesh system setup in ‘router’ mode, with a ‘bridged’ router (which is often ISP provided in most cases).<<«That’s the way I am set up now (after session with Sonos Tech).
2. Inasmuch as eero hub is currently bridged with dhcp on modem and  everything is now working I am  kind of reluctant to jump into the dhcp and assign a permanent IP to the hub  (i.e. it’s not broke “right now”...and BTW wireless is disabled on the cable modem which is physically very close to the eero hub). I am wondering what would be the upside to doing that (assign perm IP)  since the mesh gives us plenty of bandwidth and signal strength all over the house.
3. I agree with you and personally like the idea of having one component hard wired and dealing with sonos network in that fashion but it looks like eero may have decided it doesn’t want to do that anymore.  The playbar that was hard wired and misbehaved is physically close to another, non hub,  eero AP (and maybe that’s the issue?). 
4. I think if the system breaks again I might try to hard wire another component that is not as physically close to an eero AP.  That’s actually what the sonos tech did in order to finally see the system (I grabbed a play one and moved it to proximity of a cat5 wall port, then he finally saw the system but I needed to put the play one back where it was.  
   
   ​​​​​​Anyway, thanks for your response and Happy Holidays!

Just to clarify it’s all the Sonos Product IP addresses that need reserving, but it is optional. That said. I do reserve my mesh Hubs too and a few other things, like smart-plugs etc.

I don’t wire anything to my wireless mesh satellite hubs, especially not Sonos, as it can in some instances affect the backhaul. So I wouldn’t bother doing that, personally speaking.

If the system encounters issues, my initial thoughts are to go for the DHCP reservation option first, as that can help with any updates and all the devices rebooting simultaneously etc. 

Ah and yes (thanks ), Happy holidays to you also