Problems with shear cut steel warping?

ive recently started using A2, better yet tried using.. Ive heat treated 5 different knife blanks that I made from stock removal and every one had an insanely nasty warp in it.. the first 3 were beveled to a .02” edge and plate quenched, the 4th and 5th were just profiled, 4 was plate quenched and 5 was quenched in still air in garage at 40 degrees ambient. Heat treat was in oven foil wrapped at 1225 for 5 minutes, 1400 for 5 minutes, 1750 for 35 minutes then quench.

I’ve asked some friends for input and from what we’ve gathered is that maybe the steel was shear cut and causing my issue of a bad warp? I’m talking an 8” knife and in the middle would be over a 1/16” gap when I lay it on glass.. the picture below is of a blank that was half warp corrected during a temper.. any help is appreciated as to why all my A2 is warping!

 

Thank you, when I do this do I throw the blades in, ramp up and hold for 10 minutes or so then shut the kiln off and leave them in?

 

I’ll give it a try, thanks!