Hi, is this still happening on the latest release (127)? Previouisly I was linking the profile button to go to your account ID and I think you and that other account share an id just on different instances. Now it should be specifically retrieving your id on your home instance.
I tried testing it out in the connect app by going to a link you commented on and clicking I think what is your mtgzone username and it correctly took me to the correct profile for me
Something similar happens to me, when I login to the desktop site on my pc. I'll briefly see a different username in the top right, before it switches to my own. It's never been the same other username either, and so far, has also been actual users that it has shown me.
So based on that, I don't think it's Connect doing this to you. But I don't actually know.