iPhone X front camera shadow

[Amanpreet96]

Hi. I have been using the iPhone X’s front camera in recent days and have faced no issues when taking selfies. However, this morning, I noticed a faint shadow appearing on top of my head when I attempted to take a selfie (see attached photo above). Subsequent attempts resulted in the same outcome. This is not very obvious, but evident in front of a white background if you look closely. Any idea what could be the issue? I am currently on iOS 11.1. Not updated to 11.1.1 yet. Have booked an appointment with an Apple genius for this Wednesday.