OK.
What might be happening is that the warp is causing one edge to be longer and sharper than the other (which will not be very sharp) in one part of the blade (e.g., in the center), and the other edge to be longer in another part (e.g., the ends). Somewhere in between, they will be the same length and sharpness. Or maybe they will the same length at the ends (because that is where the skate tech usually adjusts the machine), but longer and sharper on one side in the middle. Gravity will try to push you to tilt (or twist) towards where the edge is short. And since the blade is less sharp there, you will tend to skid on that part of that edge.
Let me explain why a warp could cause these problems:
The sharpening wheel first is "dressed" (ground) to have a circular cross section somewhat like a coin. Think of it as an abrasive penny that sits sideways across the bottom (hollow) of the blade. In fact, it will be used to create that hollow, and therefore the two edges along the sides of the blade.
(That's not quite right, because the wheel rotates along the blade - but let's ignore that rotation for this simple description. Also, in most sharpening machines, the bottom of the blade is actually mounted to stick out sideways, so the wheel rotates in a horizontal plane - but ignore that too.)
Now if the penny is exactly centered on the thickness of the blade it will grind a symmetric shape, namely the hollow, and the two edges, formed by the intersection of the hollow curve with the sides of the skate, will be the same shape, except they will be mirror images of each other.
But if you push that penny over to one side, so it is no longer centered across the thickness of the blade, the edge on that side will be shorter, and be somewhat rounded off. So centering is critical.
Pro shop sharpening machines let you adjust the centering of the wheel (in our simplified model, the abrasive penny) across the thickness - sometimes at one point along the blade, but the better ones let you adjust that centering at two points - e.g., both ends of the blade.
The blade then travels in a straight line along the wheel, following the shape of the blade, at least if that blade is straight, not warped. That should do a perfect job.
But assume the blade is warped. That straight line of travel does not follow the warp of the blade. So, it will be centered differently on each part of the blade, and the two edges will be different lengths along different parts of the blade, and it will not be all that sharp on both edges on most of the blade. Even if your skate tech is very good.
(On some machines, the skate tech holds the boot in his/her hands and rests the blade on a table next to the wheel, and they could theoretically tilt the boot and blade a little to compensate - but that would require very steady hands and very high hand control and skill to do it right. So let's assume they can't do that.)
High end figure skate pro shops have an expensive blade holder that clamps down on the whole length of the figure skate, and forces it to be unwarped - at least while the blade is being sharpened. So the "penny" stays centered along the whole length of the blade, and both edges can be sharp and of the same length.
But the fancy blade holder/clamp doesn't fit hockey skates. Since most pro shops do most of their business with hockey players, it isn't worth it to them to buy that fancy tool. They may not even know about it.
Warped blades are a case where good hand tools like the
Pro-Filer can do better. It has a 3" long abrasive cylinder instead of the abrasive coin that we imagined. Like the coin (or dressed wheel) it has a circular cross section that rests across the hollow of the blade. It is placed and held within a handle that has a slot the blade fits into, to force it to be centered across the thickness of the cylinder. It is then slid along the hollow of the blade, grinding it to the proper shape. (That is slightly oversimplified, in part because the gap size may not be exactly right for your blade, but you get the idea.)
In theory that should have exactly the same centering problem as the sharpening wheel, because the cylinder is straight, and doesn't follow the warp of the blade. But 3" is shorter than length of the blade. So the warp creates less of a centering problem.
There was another older hand tool - the
Berghman sharpener - that only had a 2" long cylinder. (They are less expensive on
eBay, but the picture on Amazon is nice and clear.) Since it is 2" long, it would have even less of a centering problem - though the original cylinders were made of a type of abrasive stone that crumbled, and they also used a rather coarse abrasive that worked fast, but didn't create quite as sharp an edge. But if you replaced the cylinder with a more modern material, it would probably do better than the Pro-Filer. Plus, unlike the Pro-Filer, it also had an adjustable gap size, was essentially self-centering, and it let you see what you were doing better, especially when working near the toe pick, so it was a better design, IMO.
Both these tools have limitations. The kit with gap sizes wide enough for figure skates only comes in 3/8", 7/16" and 1/2" ROH (radius of hollow) versions - and the 7/16" kit, last I knew, was actually 3/8". And the Berghman tools only came with 1/2" ROH. Since 7/16" ROH is what most figure skaters choose, and some choose custom radii, neither tool is ideal for some figure skaters. In contrast, good pro shop sharpening machines let you dress the wheel to arbitrary radii. Plus, it takes time to learn to use any tool yourself, and you may have to learn by making mistakes. But it sounds like the skate techs you found in Canada are also learning from their mistakes, on your expensive equipment, and are trying to work around hardware that can't do the job - though perhaps the second one could if he/she unwarped (dewarped??) the blade. (I'm a little worried when you say that all the warp is right up front. If it is a major bend, that could mean that unwarping it would cause it to break.)
Did you ask around to see if you can find a really good figure skate tech in Canada that you can get to? That is still likely to be the least trouble-prone solution for you, and you don't need to worry about learning to use tools yourself, or figuring out what is going on.