1995 d nickel struck on T1 blank
Scored this coin on ebay. The following is my amateur interpretation. Corrections are welcome!
From what I can tell, it's a nickel that was struck on a blank that managed to slip pass the annealing oven, washing station, and upset mill before being struck. Having skipped the annealing step, the blank would have been abnormally hard and it's this that's caused the 'weak strike' look. On the rim (apologies for bad pics), you can see the shear and tear marks left by the blank cutting machine. No clue about how common/scarce this kind of error is - just think it's interesting!