I have several other 2.4Ghz devices and they never had an issue connecting and with the Guest Network turned off the 2 problem devices are rock solid. So weird since it's a different SSID that was disabled. But I'll take it. When I have a party I can turn it on and let the 2 devices disconnect...
So I upgraded from an AC-86U to the BE-86U and ran into something really strange. In setting up the BE I used temporary SSID's and did all my static IP configurations that I needed before I switched over. Then I powered off the old router and renamed the SSID's to match what I had previously...