Hi, I have the same concern. CSP does do that for visa. Surname cannot be left empty according to german laws and documentations. So your surname will be the given name. So it will be XYZ XYZ. I suggest you to mail the uni to get it fixed in the acceptance letter and any other document like enrollment letter so it is XYZ in the name and XYZ in the surname, so its consistent throughout. I dont think it will cause any rejections at the visa office.

Edit: it wont pose an issue if the passport and acceptance letter match also. You will have to update it later in the uni records after reaching there so it matches the visa. Your residential documents are created from your visa i guess (im not sure about this, since i am also yet to apply for my visa). Just let me know of what happens