2001 Dime, Die Chip Or Gas Bubble?

Not all bubbles and blisters will look the same its almost impossible, some will be minor, some will be major, some will be round, some will be linear or oval or in clusters all over the surface like your 2000 W cent you posted.

An you are correct, most bubbles tend to be the result of heat after leaving the mint, the heat could have happened for many reasons either on purpose, or left outside in the hot sun in a parking lot or a dryer.