@JohnOCFII:

Seeing that this setting has something to do with power saving mode and QoS, who knows - this could be related. I do not see a setting specific to just WMM.

Yep, "disabling WMM" practically means "disabling WMM APSD". Even the page you've linked mentions that it can be linked to connection dropouts: "There are reported cases of mobile devices dropping connections when the WMM APSD options are turned on."

As I said, it seems that disabling it resolved the issue for me, so it's worth a try if anyone faces the problem. Probably the worst thing that can happen is that they'll have worse battery performance on their mobile devices for the time of the test.

I experienced the same issue on a new Duet Wifi I received this week. I recalled that I had similar problems with some devices in the past with WMM mode enabled on the router. And indeed, disabling it fixed the issue. I have a router running OpenWrt based distribution, which allows to enable/disable WMM on per-SSID basis. I'm not sure about other routers, such as those ASUS devices mentioned here, but I think it should be at least possible to toggle WMM globally to try if it solves the problem.