Hi @Alexandre. I had that arrangement initially. Same problem occurs. Has behavoir like this been reported before?

@David-TP Thank you. Yes, that connection between the 2 dumb switches is just CAT6 ethernet cable (100 feet or so). Have you ever heard of cases like mine? Where it works fine but then occasionally...

I have 2 Deco's for wifi access connected in a mesh, AP mode. They are 100+ feet apart and in seperate metal buildings (no way for wifi backhaul). I have them connected as you see below - not with a...