Do you have a screenshot of how this "weird text" looks? I don't know what you mean by a hidden text in the middle of the screen.
The question is also where you have this problem: In the browser or on a smartphone or another device?
I don't have the game yet but I did read you have to do the following:
To play TESO on Stadia, you'll first need to create an Elder Scrolls Online account (if you don't already have one) at https://account.elderscrollsonline.com/ and then link it to Stadia at stadia.com/linkaccount.
Otherwise I've heard there will be some sort of invisible box. Not sure if that is the issue. Hope it helps.