@Flyer58uk 

Good day,

Thank you very much for your time and patience.

When the Wi-Fi disappear, Did the wireless LED still lit up?

If you unplug it and plug it somewhere else, and reset it again, would the same problem still exist?—(please unplug the first adapter first and only power on the abnormal one)

Where are you located and where did you buy the powerline kit?

Thanks a lot.