While going through a few jars of coins searching for errors, among a few errors, I found this interesting 1990 Lincoln cent with missing letters and some doubling. I also noticed that the rim looks different from other business strike pennies. The rim is not beveled and wider when compared to other business strike 1990 pennies. Here are some pictures. Looking for some opinions. Thanks.
What you see is caused by an overused Die. Worn Die strike cause your issues. The missing letters is debris build up on the Die that did not allow them to be formed properly when striking the Blank Planchet. Any doubling is DDD - Die Deterioration Doubling. Nothing major.