Found This Pinocchio Roosvelt 1978 Dime

It's not a gas bubble issue, more of an expansion issue with different metals and clad thickness. they get flattened after someone tries to use them in a vending machines and they are to thick. They then smack them with a hammer, then use them.

Thank You Halo1st;
That is very interesting,it sounds like there is a problem with the mixed metals being bonded sometimes ,and it would be very difficult to tell how these bubble's actually were made ,inside the mint or outside the mint.I'm guessing with my coin
just guessing .I have seen coins that have been grease damaged
and it looks a lot like this coin.Their is something going on with the dark discoloring and pits in the coin metal.Maybe fire, but would that cause pits or maybe it was just in the ground and decomposing? But I'm thinking what ever caused the pitting did it cause the bubbles too, I'm thinking it did.

I'm adding another mystery to this coin why does it weigh only 2.18 grams
When it should weigh 2.27 grams .Could that mean it was pitted in the center causing the weigh loss and causing a bubble .