Installed 384.16 the other day (upgrading from 384.15), on both my primary router (86U) and my AP (68U). The upgrade went fine on both devices. And for 2 days, all was fine. This morning, I noted that while in portion of house near the 86U, my phone (Galaxy S20) was not connected to WiFi. I tried connecting to my 5Ghz network - would not connect. Walked to back of house (near 68U), phone connected just fine. Tried same thing with my wife's phone (iPhone) and same basic results. Phone would attempt to connect, sometimes reported an authentication error (haven't changed password for a very long time) and sometimes not. I tried connecting on the 2.4Ghz network, and that worked fine with both phones. Rebooted the router, and problem went away. But this is something that hasn't happened before.
I noticed the same thing so I change from the 20/40/80/160 option to strait 80Mhz for the bandwidth that sorted my iPhone out here.