Rog, I wouldn’t call that a warp. It’s only normal to have to adjust the washout.
Only problem is that nowadays with plastic wrap it takes three hands. Two to hold the wing and a third to hold the heat gun. I remember (and bet you do to) the old stick and tissue models. Bring the teakettle to a full boil and pass the wing over the spout. Only took two hands back then.
Cheers, al