Found this small incuse on the reverse of a 2021 cent and I'm at odds as to how it got there. I don't believe it to be damage due to there being no marks around it and it's simply too clean. At first I thought it was some sort of clash, but that would make no sense because it is an incuse. Any help and/or opinions are appreciated. In the picture through the loop, the incuse is located at the top of the stripe directly under the "R" in "PLURIBUS" and the "E" in "ONE."
Looks like a square indentation. Might have been some sort of strike through some metal debris, but more likely took a hit from something.