Have this exact problem as well, not on all websites, but basically randomly occurring without any clear patterns. Happens a few times a day. Sometimes it happens when trying to log in somewhere and there's a 2FA moment, and the reload just happens one time, taking me back to the initial username/password screen. Sometimes reload happens on a loop; I had a site (https://demo.linkding.link/login/?next=/bookmarks) earlier today that was reloading on a 6-second loop cycle, endlessly.
Automatic user agent for the most part, except when the site breaks and wants Chromium.
Currently: Orion Version 0.99.132.0.3-beta (WebKit 621.1.2.111.4), MacOS Sequoia 15.3.2