@David-TP Thanks. I didn't notice there was newer firmware available. I did some additional testing and my problem might after all be some kind of cabling issue. After moving my main Deco on other...

I have following mesh setup with 3 Decos (X1500 aka. X10): Fiber ONT --- main Deco --- Switch (TL SG108) --- satelite Deco 1 \---satelite Deco 2 Decos are in router mode. QoS is disabled. I also have...