When you attempt to publish a model to ROBLOX and there’s an error where it says you aren’t logged in, it will lead you to the old studio start page. As far as I’m aware, that was removed in place of a new studio UI/login system.
I don’t know how to explain this bug (is it even one?), I just managed to stumble upon it (somehow caused my studio to crash afterwards too).
Sorry that I am unable to provide a repro file since it was a one time thing and idk how to reproduce it.