You need to look at the numbers. It's very much mathematically possible. And it's not even that unlikely to happen.
At Chris: The Panther is a tank destroyer with a turret. It's very good at killing tanks, but it's one of the worst tanks for killing infantry.
I'm speaking from experience and basing it on stats.
IS-2 can handle healthy panther, it will loose most health, but will win.
There is no way to loose IS-2 to a panther that drove over a mine, unless soviet player was most unlucky player in CoH2.
Healthy vet1 panther will eat IS-2 alife, but damaged with engine damage simply can not, unless IS is weak already.