I don't think it's a problem, it's just how it intentionally works. The problem is they don't render the account switcher when you arrive to a new product that your current account hasn't signed up to.
but basing accounts on urls not cookies is really dumb, especially when people send mydocs.google.com/u/1 which refers to my team but i'm logged in to that team on mydocs.google.com/u/2 or the 0 based one which doesnt even get a namespace