This is definitely in a Very Late Die State. It's pretty common for the 1980's. That little "ridge" thing is from heavy die wear from all of the pounding the die had to do for all of the strikes. This is a normal reaction for Copper plated planchets.
More information about Die Deterioration
Retired U.S. Mint Coin Die Set information. http://goccf.com/t/302961 Machine Doubling
Die states progression on coins. Scroll down, so you can see the different die state progressions. http://goccf.com/t/325638 Die Deterioration Doubling
Split Plate Doubling Tutorial. http://goccf.com/t/357614
2000 P LMC
With Retained Struck Through error. http://goccf.com/t/357080