Even after changing my password, I couldn't login to my email on my phone, so I just gave up. I only use that email for a handful of things anyway.
Isn't this only if browser have some cookie from previous session or IP didn't change?
Edit: just tried (new IP + private window firefox), you are right, I can enter email and select app notification.
It freaked me out the first time, I went through all the security settings I could find, but it was if it never happened.
I just ignored it the second time, but it's a bit unsettling, because the default authenticator flow also has the chance of accidentally hitting the right number.
1 in 3 and easy to hit by mistake.
I can only envy your adroitness.