I have noticed that Grandpa Gohan is regenerating. Does he do that in the original Dragon Ball? (I haven’t watched too much of the og to confirm)

I believe it's because he's a (spoiler alert) ghost.

That's an awesome detail! Love it. 😄

But thinking about it, he shouldn’t have regeneration. This is the same case as Goku and Vegeta with the halo: they take damage from Buu and say that if they die, their bodies will be lost forever.

This will be removed in the upcoming update.