That's what I meant with "full support" - this new user has no relays in kind:3, and you're not reading from kind:10002 - so which relays are used when they post? Only your relay? Some default ones? 

 I'm not sure how it works, in that case posting just shouldn't work. @moysie should know more about how web app works. Maybe it reads relays from the extension if it's setted up there.