Exactly the same issue. I'm extremely disappointed with tp-link. I've connected my deco devices via ethernet backhaul, so they are connected in the most efficient way, but the WiFi on the X10s constantly drops. I'm running latest firmware.
This is obviously something tp-link is aware of, since that setup is very easy to replicate and confirm via tp-link internal testing.
So my question is the following: Will you fix this issue via a firmware update soon? Or is this something that can't be resolved on X10 devices due to the chipset construction?
If this known issue can't be fixed, then please communicate that now, so that I know if I should keep on waiting for a firmware fix, or if I should throw the X10 devices away.