It's tough to say. I think you already know this, but PMD is Post Mint Damage. I agree it's unusual, but copper is softer, so it could be anything.
Aomekie Handheld USB Digital Microscope 1-200X Zoom 2MP 1600x1200HD Imaging Endoscope Magnifier with 8 LED Lights Health, Collections, PCB Inspection Sold by: Aomekie scope Bought it from Amazon for about $60. I use it with my PC.
@Granbeck , what is your collecting style? varieties? errors? small cents? Do you consider yourself an "expert" in any specific area? BTW, welcome to Coin Talk. This is a great site for collectors and numismatists alike.
I was left a big bunch of coins by my parents, and my husband has been saving cents since we were married 52 years ago. Right now I'm just easing through to see what I have. Before the first of the year, I had never heard of varieties or errors or small cents, so no, I'm an expect of nothing. Thanks for your welcome. I've been reading Coin Talk for a while before I joined. I appreciate all of the help.
It looks to me like someone poured melted metal across the "t". It's hard for me to picture how that could happen any other way. It's very interesting.
In your first picture of that area, it looks raised, in the second picture (more of the entire coin) it looks recessed. If it's raised, than I'll need to rethink it. I doubt it's a mint error. I still believe PMD, but not sure how at the moment. Do you have any books? I think a Professional Red Book or a book on errors might be helpful. Or you can just keep asking questions on this site. I buy many of my books from Wizard Coin Supply, not Whitman, but this was the first link that appeared on google. https://www.whitman.com/store/Inven...ial-Red-Book-Professional-Edition-3rd-Edition
Here are some more pictures. On the last one I tried to hold it sideways so you could see better. There's no doubt that it is raised. In a strong natural light I can see it without a magnifier. I think it is a most interesting coin.
PMD can be minimized if the US Mint, while minting would not allow each coin to pile up in a big pile and just put each and every coin very carefully in a soft flip/2x2 etc. Then distribute and tell consumers Not to use the coin outside of the flip as damage may occur such as, but not limited to: coin rolling machines; gets crammed in a coin jar and scratching each other; repeated coin snatching; playing quarters or pennies or any coin/drinking game; coins clinking next to each other and scratching and damaging each other; piling up and scratching each other in cash register; falls to the ground; make jewelry out of it and later take it out of jewelry; gets stepped on; car runs over; lawn mower runs over; someone uses in a fuse box; pliers; hammers it; lets the dog eat it; falls to the ground and is buried for a period of time; put in ash tray and gets covered in ash and damages surface; use as a screwdriver; gets stuck in washer; gets stuck in dryer; gets flushed down the toilet and stuck elsewhere; gets eaten by an alligator; someone drills a hole in it; gold plate it and sell it online as special; seagull eats it; sucked up by vacuum cleaner; dog eats it for a second time; falls under refrigerator for 10 years as gunk destroys it's pristine condition; dropped on a beach and the sand wears it down; science experiment; electrical experiment; torched; rubs against other coins; rubs against other things in one's pocket; gets stuck in a banana; thrown in fountains; thrown in rivers; thrown up by the cat; accidentally put in concrete; put in rock tumbler; just plain abused for no reason at all ... etc.
Now that is interesting. Those pictures clearly show what you are describing. I'll wait to see if someone with more knowledge can explain it. It doesn't look like there's any metal movement on the field of the coin. I see some copper movement on the T, but that's all I see. It would be a mighty funny die crack, so I don't think that's it. It's also very wide for a crack. It would be more like a chasm. Could there have been some metal shaving on the planchet and it was struck into the coin? Maybe there was a sliver of the alloy on the die before the next planchet was loaded in the die. Either way, not sure how to explain it. It's interesting though.