I've had this in an Apple silicon case it's whole life but take it out every so often to gently wipe it down. Today, I noticed some discoloration on the bottom around the speaker holes. I messed with the contrast in the pic to highlight it, but it's not too bad in real life. But just curious what could cause it and and if anyone has any suggestions to try and fix it. At first I thought maybe it was a ring based on the case cutouts but the silicon case has individual cutouts for each hole in this photo so it's not that. Not a huge deal and realize I can't probably fix it, but I'm just curious.