If I am in the website setting up some emailiases and I add a new target address, the verification email goes out, arrives at the destination, I click the verification link, a new web window opens, the email is verified, all good there.
If then I go back to the original window from which the verification was invoked, I can’t reload that page without Firefox completely dying (all windows go down hard). Restart Firefox and boom down they go again as soon as that window is reloaded.
Close that old window and open a new one to navigate to that same spot and all is well. Something very bad happens when the verification status of the target email happens to surprise the active window.
Firefox v96.0.2 (64-bit) as Snap for Ubuntu