I'd agree with Rover1822. The one thing I must say is that I have had no observable issues with my GW1100 and reception of sensors. My GW1100 is at the front of the house and my WS80 and WH40 and one of my WH31 are in the back garden so furthest from them. My GW1000 is at the back of the house considerably nearer these sensors. Both gateways show identical signal levels for all sensors and I must add that this is a 100 year old house so no flimsy walls here

OK my distances are no where near the max that Ecowitt say they should work, so maybe running at max distances may show issues.
If Ecowitt are sure there is an issue we need to wait to see what they will do but it will have to be a new gateway.
Stuart