Ok, hold on.
I have 16 gosund sp111 flashed esphome devices. All run fine. My wifi is very stable, 1 controller, 5 access points, multiple ssids. Never issue.
But…
I have a very weird problem.
When I put an sp111 in the power socket it works well. As soon as I plugin an ikea extension cord it instantly looses wifi connection. Multiple cords, multiple sp111’s same behaviour 
.
Also then the plug of the cord is in half: wifi lost. Plug out, wifi back… nothing is connected to the extension cord, just emtpy.
(Wifi lost means the gosund flashes blue and is not connected to the wifi anymore)
It is very good reproducible, but very annoying.
What can that be¿