This 1978 quarter has 2 lumps in it. I'm curious if this is something that could have occurred from mint or if something happened to it afterwards. The obverse is perfectly fine with no recess or any kind of damage at all so it is either extra metal on coin or some kind of internal bubble?
Internal bubble is on the right track. This coin was heated by an extreme source of heat. The interior copper core melted, expanding and warping the exterior nickel cladding, which has a higher melting temperature than copper. But at that temperature the nickel is in a ductile transition state and can expand to the increased interior pressure from the copper.