Perhaps a complete coincidence and an unrelated issue.
After upgrading to firmware 7.12.3 3 devices could no longer access the internet via my 5GHz wireless access point. All had the same issue insofar as the devices returned the message “Incorrect Password”.
I tried rebooting one of the devices. I tried retyping the password into the device, which didn’t work.
I tried rebooting the router and all 3 devices still could not connect themselves.
I ended up deleting the 5GHz wireless access point and recreating it with the same name and password, and alls well and working again.
One device (FreeSat Box) doesn’t specifically say or offer a choice of Auth Modes, and this setup option wasn’t offered by the device when reconnecting it to the WiFi AP. Two devices just reconnected themselves without issue after the WiFi AP was recreated without any input from myself.
All devices that are connected to my 2.4GHz continued to work without issues after the firmware upgrade.
Hmmm, could not reproduce this. Also nothing about wireless was changed between these two versions so it is quite weird behavior.
Although it is possible-ish that you have other rouge AP with same SSID but different password. You can try to temporary turn off your RUTX50 (or just AP inside it) and check if devices try to connect to something.