Ac one mini on 3.5.4 1681

I’m finding that my clients are not auto establishing a wifi connection without manually going into wifi ssids available and selecting upon a ssid. I have connected to the ssid in the past.
I also have selected the client to treat a particular ssid as priority 1 in the wifi list, but it never joins this ssid first.
The ssid I connection too versus the ssid I set as a priority on my windows 10 client are both the same, 2.4 and 5 ghz. Although the one that I connected to this evening contains a captive portal, not sure if this causes it to be favoured?