I advise you to first come up with an overall strategy for the acceptance. If that is the only defect, it will probably be fixed. If you have 100 issues in that category, you will not find a hearing with the developer and he will eventually shut down.
Keep in mind that you should maintain a good relationship even during the >5 years of warranty.
The specific tile is certainly not optimal, but I doubt that any building regulation covers it.
So, I’m not really the type of person who complains or looks for defects, I also have my “you get used to it eye.” But I would complain about THIS. You look at it five times a day. The tiles rely on their simple elongated elegance, and this really disrupts the tile pattern, let alone the fact that you can actually get it “right.”
I would also criticize that, it's not acceptable at all. Either 2 new tiles or a larger [Drückergarnitur] (which I would recommend anyway, because if you ever have to access the button from inside, your hand has to fit through).