Sorry forgot this one, mail notification settings says
"Send an email if a new chat message arrives and I am not online"
And I receive one even if I'm connected (but not on same tab) which does not match option configuration
Can you please clarify the following: Do you mean you cannot put your cursor into a field on the registration page because of a browser popup asking if you want to see notifications from this community?
Also, what browser are you using and do you have any extensions installed in it?