Is this on your "La Casa del Chef" listing, @Manuel3356 . Yes, the breakfast amenity is still showing there for me, but it is not showing on your other listing.
Last week I was trying desperately to change one of the "You must also acknowledge" items in my house rules. I changed it and saved over and over on my laptop, and it would say it was changed, then revert back as soon as I looked again. So I tried it through the phone app, and it worked the first time.
Do you have access to another device to try to make the change that way?