There are tons of Jalapeno strains out there.
Some are stable Hybrids that are really hot as far as Jalapenos go.
I found some giant ones at the store that were almost as hot as a generic orange habanero.
I've also baught some that looked the same that had almost no heat too.
Hopefully you have a stable variety or strain of jalapeno that will put out heat for years to come.

Thanks, makes sense. I didn't realize that there were jalepeno strains that got that hot. Looks like I've got a good one.

Probably cross pollinated plants