Hello. I have this weird issue.... I've read a lot about it and how there's no solution.

I have three Decos: two at home, one outside home, in a small office.

Deco 1, let's say, is the office one. Deco 2 is first floor. Deco 3 is 2nd floor.

My house is built out of hard materials. That's the reason for using Decos.

Deco 1 works fine. Deco 2 works fine.  Both Decos are in open spaces.

Deco 3 is almost in the middle of a hallway. There are three rooms with brick and mortar walls around it. 

If I only use Deco 3, signal is great on my 2nd floor. Every device gets at least 60% of my full internet speed. No issues.

If I use Deco 1 and 3, I have no problems, but I get no reception on my 1st floor (obviously).

When I use Deco 1, 2 and 3, devices on my 2nd floor connect fine at first... then after a couple of minutes, start roaming to from Deco 3 to Deco. 2. Deco 2 is too far away and has basically no reception. Yet all devices refuse to connect to the nearest Deco (2). I basically lose all Internet connectivity when this happens and it happens all the time. Then, suddenly, devices reconnect to Deco 2 and everything is fine.. for a couple of minutes.

I've disabled Fast Roaming and Beamforming. No use. I've changed the main Deco. No use. Only thing that works is killing roaming on each device by using the Deco app. And then, I ask why I bought a mesh system that does everything but a mesh...

Please help....