Issues with Chromium-based browsers and SSO access?

Hey all, 

We've recently ran into a strange issue with UFT Mobile 2022 and SSO - suddenly, it started giving the generic NGINX error page right after the authentication process, but ONLY on Chromium-based browsers (Chrome, Edge). Everything works perfectly fine on Firefox. 

As far as I gather, there have not been any updates on the server (it's UFTM on-prem) and if it was some Chromium-related update, you'd imagine the web would be full of posts about the same issue. Nothing. 

Now, disabling SSO is not an option, even temporarily (it would would reset all the accounts AND is against company policy), but I do kinda suspect something in the way the SSO authenticates has changed in the backgroud...but why the failure on only one class of browsers? 

Final step to the mystery - updating the server to UFT Digital Lab 2023 has fixed the issue, without any additional updates/changes. 

Any ideas?