Hello @David-TP !
The issue does not occur often... which will make this a little difficult to diagnose.
I have roughly 30-40 clients split between my Main (15-20 clients) and IoT (18 clients).
I have 3 TP-Link Easy-Smart switches running 2 VLANs (Deco Network, Non-Deco Network).
Deco satellites are Ethernet backhaul on Deco Network VLAN.
As for the sequence of events, that is hard to determine prior to devices dropping.
What happened yesterday was this:
My oldest son and I were gaming on 2 different laptops (both wired on Deco Network VLAN). Same game, same server.
Wife was on her Work Laptop (wired on Deco Network VLAN) connected to her work via Cisco VPN Client.
Son's game timed out and he could not reconnect (even after rebooting). I was still connected and playing.
I jumped on his laptop and it showed that he had an IPv6 address but IPv4 was auto-configured (no DHCP).
I did an "ipconfig /release all" and "ipconfig /renew" and no address was given.
Shortly after, wife reported that she was booted from work VPN and cannot reconnect.
I opened the Deco app on my phone and it only showed 6 clients connected (mostly wired but included my phone).
I went in the the DHCP settings and changed the starting address from 192.168.1.100 to 192.168.1.99 and then reverted back.
Everyone was able to then connect and the client count went back to normal.
NEW INFORMATION:
A couple of hours later everyone got disconnected again.
This time I could not connect via the app so I had to perform a hard reboot via power cycle.
For reference, the Deco's had been powered on and working for well over 2 weeks prior to this.
Again, this seems to be a rare event and happens during heavy use.
As soon as it happens again, I will save the logfile and send it to you.