$2 Coin Planchet Flaw?

Not sure by what you mean by this ... as depicted in the photos, there is metal missing from the area in question so wouldn't it follow that the coin will be underweight regardless of what the cause was?

Due to it's shape and positioning I'm thinking that it's most likely the result of a folding cold shut that has detached.

A detached folding cold shut looks to me as being plausible.
To my eye, it is less likely to be post Mint damage gouge.

If either of these explanations, happen to be correct, it should weigh slightly less than standard weight .

If the first explanation is correct, then it is an error coin.
If the second explanation is correct then it has sustained post mint damage.

On reflection, under these circumstances,
I have to agree that a weight measurement may not be much use in a determination.

Perhaps a close look under high magnification may reveal if there is any post Mint gouging damage,
but at this point of the discussion, I am inclined to agree that a cold shut detachment is more likely.

Thanks guys and sorry for late reply, this is pic of reverse




Sorry about quality, the size restrictions make it hard with a mobile phone