Interesting! – Honestly, the thought that it might have a connection to using Brave also occurred to me yesterday. There was this thread a few weeks ago: Google accounts keep logging out in Brave after installing Bitwarden extension – and I also made a post in there about Brave causing reauthentication requests on a certain banking site literally every few seconds.
But I mainly thought of the 2FA recovery code not working “because” of Brave (speculation!)… so, interesting find, that email verification seems to be “browser dependent” (to a certain degree 
).