I just found this coin in change and thought it may be struck through grease. Like the TEN in TENNESSEE is faded.
I have the impression of a *slightly* tilted die making the strike a bit weak in that area - check the corresponding area on the obverse, at QUARTER. See how the bottom of the letters are "ridged?" I believe that could be due to incomplete die filling due to incomplete pressure from the tilted die. Then again, I'm just theorizin' here.
Might have a SLIGHT fill but not significant and not worth more than face value. Isn't even significant as an "error" because the letters are almost completely there.
At SuperDave is a very smart collector. Sometimes it seems he will over-think a question and share several different theories to explain simple things. What he is saying is that the die did not come down "flat" on the planchet when your coin was struck. In that way one part of your coin was fully struck while another part was weak. I don't share his theory.
Actually, If you ever get the chance to speak directly with a TPGS employee (in receiving/shipping/or the grading room) they can tell you that many coins like the OP's are sent in for grading. Would you believe 2015 Lincoln cents that barely make MS-65 Red!
If you look closely on the reverse, just below the star the farthest on the left, there appears to be a die-chip in the shape of a running chicken. At the bottom to the left of the guitar seems to be a smoking peace pipe.