Maybe a coin that was spotted as defective and meant for mutilation and discard? Looks like it was coined missing some of the clad prior to the damage.
http://www.error-ref.com/partial-clad-layer-before-strike/ http://www.error-ref.com/missing-clad-layer-partial-after-strike/ Ouch!!!yes I was thinking the same @SensibleSal66 can you weigh the coin and get some edge pictures.
Try to get some better photos. It appears to be missing the clad layer and the cut may have been pre strike.
I don't think that was a cut by a tool, so I'd vote for a damaged planchet with missing cladding. Just my guess. Very interesting to say the least. Wonder what a TPG would say. Maybe @Fred Weinberg could chime in.
@SensibleSal66 That coin is worthy of keeping until you can find out more about it. Personally I don’t think it was damaged.