Just going through a penny roll I got at the bank today. Check it out. Any info would be helpful. I don't see any scratch or dent from other coin striking the 5.
It's definitely post-mint damage, but there is no telling what may have caused it. It looks too straight to be a bag mark from another Lincoln cent. Chris
If it were a die break there would be something there to fill the void It would look something like these two. Not my coins
PMD, suspect middleman counting or crimping machine. They use ballistic bins I believe rather than bags in 2015.