I recently bought my first monochrome setup, Antlia's LRGBSHO set. After placing them all in the filter wheel, I looked down and noticed a spot on the telescope-facing side of the red filter. I picked it up and looked at it pretty well on both sides, and from what I can tell, there's zero surface abrasion visible i.e. if it was a chip in the glass, I assume I'd see a little divet or chunk missing. Seems smooth though. I wiped it carefully with a microfiber cloth several times to see if it was a liquid mark or something, but it didn't wipe off.
Images - https://imgur.com/a/Kvpsekc
1. Anyone have an idea what this is? I can't rule out that it 100% wasn't something I did, but I don't know what I could've done to make that spot, without realizing it when I may have done it
2. Will it even matter? Maybe flats would take care of it?
3. Should I reach out the retailer I bought it from? I've never tried to return or ask for a replacement for anything before and so I don't know if this is something they'd consider