Went through my pocket change this Friday & the only piece of change that caught my eye was a 1983 LMC. I'll place it in a 2x2 and mark it "Poor Baby".
Do you have a photo of the edge of the coin? It's hard for me to wrap my head around this one. If it's die deterioration or a collar clash, the metal should be raised beside the rim.
BTW, I weighed it 4 times on two different days. Day 1= 2.488 and 2.487. Day 2= 2.488 and 2.489. So, it's w/in tolerance for a normal Zincoln. Will definitely place my 'strange but true' folder.