I'm curious if anyone has noticed the jaw/beard line on Lincoln penny being inconsistent. I've been going through my pennies and on the 1993 Philadelphia mint penny I've found two; out of several hundred that I've checked, have a weak beard line running from Lincolns ear down along the jaw line. I thought maybe a weak strike or something but this seems like kind of a strange place for this to occur. I've attached a picture comparing the two; strong line on left side starting at bottom of ear and weak on right side for opinion.
I thought maybe that too but unsure because the lower lobe of Lincoln's ear sets higher than the hair line so I figured if there was going to be deterioration it would occur on the lobe not on a spot lower. Although I believe a coin strike is suppose to be even across the entire face of coin so I'm assuming deterioration could occur anywhere on a coin.