Question Phone won't use WPA2 connection once it has seen a WPA3 connection

[Calab]

I'm using a Pixel 7 phone with Android 15, build BP1A.250405.007.B1. My wife uses the same phone and is seeing the same issue...

Our internet is provided through an XB8 cable modem. This modem supports 2.4Ghz, 5Ghz and 6Ghz. Usually our phones are connected using 6Ghz, but if we stray too far we lose the connection. It refuses to connect to the 2.4Ghz or 5Ghz networks, even though the signal is strong. I get a message similar to "cannot connect with the current security settings".

I've verified this by connecting my phone to the 6Ghz network, then disabling 6Ghz on my modem. I would expect the connection to simply switch to the 5Ghz network, but it refuses with the above mentioned error. The only fix is to forget the network on the phone and re add it. This mostly fixes the connectivity issue, but it leaves us without the 6Ghz network.

The 2.4Ghz and 5Ghz network are set for "WPA2-PSK (AES)" authentication while the 6Ghz network is set for "WPA3-Personal only". For some reason I cannot change these settings. (I will be contacting my ISP)

What security setting is my phone talking about? How do I disable this so it will switch between all three wifi connections?