Rolex sapphire crystal damage?

[brandobot]

I have an imperfection on the date magnifier that looks like a smudge that is going vertically. (See photos)

Rolex store is telling me that it’s a scratch on the anti reflective coating; however, all my research here tells me the coating is on the bottom of the magnifier.

The “scratch” is not noticeable by touch. It’s as smooth as new. The dealer tried rubbing it off with alcohol and a microfiber to no avail.

Anyone know what may have caused this?