We don't know for sure there are different Nadia.
This is one reason we don't know for sure. Not knocking you in any way but mistakes happen. It's just as likely, probably moreso, that any mistake is on our end.
No the pollinator won't affect stem length. I don't think rootstock will either.
I'm waiting as well. Mine are still hard and I'm well ahead of any others I've seen pictures of.
Chances of this being a sport are way way less than a mistake or something else we're missing.