Why does desktop site get stuck/broken?
This is the same issue as reported here, but the thread is archived: https://support.mozilla.org/en-US/questions/1380035
Firefox android v117.0.1 On a Samsung A52 running Android 13
When any webpage is loaded in a tab with 'desktop site' enabled and then that tab is unloaded from memory (usually by viewing another app for a couple minutes then returning to Firefox); upon returning to that tab, the page reloads as the mobile version, however the 'desktop site' slider is still enabled and will not disable when touched.
From here the only way to actually load the desktop site again it to close Firefox by removing it from recent apps, then when re-opened it will load the offending tab in mobile view with 'desktop site' off but responding to input again.