It maybe a stain on the planchet. It was figured in with the grade. If you missed it before you bought it, then it's your fault. But stains on the coins are accepted, but lowers the grade in 'eye appeal '. Doesn't disqualify, the coin, but lowered the grade. Makes it a tuffer sale when you sell it. But keep it. When you make a mistake, keep it as a reminder to be more alert on buying your next coins. Life is a class. You learn, or keep on making the same mistakes over an over...You either learn or keep making the same mistakes.
I see that there is no consensus as too what this is on the Coin. I purchased this thru a internet dealer Photo's did not show problem. I've contacted him and PCGS with no comment yet. Note there is a small error on the middle of the chin. which does not appear on other Grover Cleveland coins I've looked at PF-69?