Shelly IoT Devices (Switches) Drop off Network with kernel 'not mesh client, can't delete it' messages

[jksmurf]

Hi

I have 2 Shelly 1PM Gen3's switching on and off Hot Water in the Main and Annex HW Cupboards.
They are on the 2.4GHz Wifi. None of my other 20-odd Shelly's have this issue.

Annex DCA:0C:B1:0A:18
MainHWC DCA:0C:B1:00:2C

They keep dropping off the Wifi at (every time) almost the exact same time.
They mostly come back up after 12-15 hours or so, not always after a Router reboot either.

The Router Logs show this:

Jul  8 18:08:16 kernel: DC:DA:0C:B1:0A:18 not mesh client, can't delete it
Jul  8 18:08:16 kernel: DC:DA:0C:B1:00:2C not mesh client, can't delete it
Jul  8 18:08:27 kernel: DC:DA:0C:B1:0A:18 not mesh client, can't delete it
Jul  8 18:08:27 kernel: DC:DA:0C:B1:00:2C not mesh client, can't delete it

Forum Check:
Seems a few others have had this with "Ignore" and Bump" and "No Solution" being go-to responses.

• https://www.snbforums.com/threads/not-mesh-client-cant-update-its-ip.73002/
• https://www.snbforums.com/threads/not-mesh-client-cant-delete-it.78274/
• https://www.snbforums.com/threads/s...address-not-mesh-client-cant-delete-it.77909/
• https://www.snbforums.com/threads/asus-rt-ax92u-new-firmware-3-0-0-4-386_45898.75132/
• https://www.snbforums.com/threads/ai-mesh-keeps-dropping.85263/

I do not use scribe. I do have Traffic Analyzer Statistics turned on.

I am leaning towards me needing RC Snubbers wired to each HWC Switch device (see Voltage Spikes, not sure if that is an issue or not), but if it's a Router Issue that is easier to fix (remotely).

I am on Merlin 3006.102.4 on an RT-AX86U Pro with 3 Mesh Nodes.

Would really appreciate any advice, it is driving us bonkers.
We changed the Shelly's from Shelly 1PM Gen 2 devices to Shelly 1PM Gen 3 a year ago thinking it fixed it, but it's happening again.

Thanks!