Since a few weeks I have a network of 3 Deco M5 units. I have a desktop PC with a TP-link Archer T4U Wifi USB adapter which is already operational for 2 years.

I run into  problem that at irregular intervals teh ping time on my desktop pc goes up to 1 second with 25% packet loss. Sometimes I do not notice it for days. Other times I notice it several times per day. I never had the problem before I had the Deco M5 network. En example of a ping trace:

23:13:03    13 milliseconds,  221 ms average,  25% loss
23:13:05  ERROR: Request Timed Out, average  221 ms,  25% loss
23:13:06  ERROR: Request Timed Out, average  221 ms,  25% loss
23:13:07  ERROR: Request Timed Out, average  221 ms,  25% loss
23:13:08   970 milliseconds,  297 ms average,  25% loss
23:13:08    11 milliseconds,  279 ms average,  25% loss
23:13:09   218 milliseconds,  297 ms average,  25% loss
23:13:10   170 milliseconds,  224 ms average,  25% loss
23:13:11    94 milliseconds,  229 ms average,  25% loss
23:13:12   237 milliseconds,  244 ms average,  25% loss
23:13:13    73 milliseconds,  214 ms average,  25% loss
23:13:14   118 milliseconds,  220 ms average,  25% loss
23:13:15   140 milliseconds,  209 ms average,  25% loss
23:13:16    11 milliseconds,  184 ms average,  17% loss
23:13:19  ERROR: Request Timed Out, average  184 ms,  17% loss
23:13:20  ERROR: Request Timed Out, average  184 ms,  17% loss

When I connect my Desktop PC to the router with a cable, the ping problem disappears.

My iPhone, which is on the M5 network, doesn't show the problem.

My laptop, which is on the M5 network, doesn't show the  problem.

My conclusion is that teh problem lies in teh interaction between the Deco M5 and the ARcher: both TP-Link products.

Any suggestions what to do?