When I replaced my little plastic cover with a premium tempered glass protector from Amazon seller AOUCCG Store the fingerprint sensor was not working and then I erased my fingerprints and tried to do new ones and it wouldn't pick them up. Is that an issue for the S21 Ultra and tempered glass protectors. When I look at the glass I see a circle in the glass where the fingerprint sensor would be. I don't know why that's there and could that be stopping the transmission?