I have a Harman Accentra that is about a year old. I do a thorough cleaning on almost weekly but I cannot say I have seen this spot right at the exhaust, post fan. It looks like a dig/knick but when hit with a flash light looks like a screw/nut head. But it also looks like it could go completely through... I took a few picture. Anyone else notice this on their's? Or know if my stove is at risk in anyway? Like I said, it could have been there all along and I've never noticed it but I don't remember ever seeing it before. I only use an ash vac with soft brush tips.