I've also had this happen. It's definitely the tune. There are a bunch of things that can go wrong with a tune. When they go wrong, the skier thinks it's them until they understand what exactly happened. This has happened to me several times, and it sounds like it's happened to others posting here as well.
--The black base must be flat. Someone should check with a "true bar" to make sure it's flat. If it's not flat, the edge bevels can change from tip to tail. Ask the shop where you have it worked on this time to check and tell you if the bases are flat. If they aren't, that might be your problem right there.
--There are two bevels put on the metal edges of your skis. That piece of metal probably does not have a 90º edge, and the edge is tilted relative to the ski. Look up edge bevels for an explanation. There's the base bevel and the side bevel. You don't currently know what bevels they put on your skis. The shop guys said they tuned "to factory specs." That phrase implies that the factory has a base bevel and a side bevel that they always use for this ski, which is probably true, and that those are published so that the stop guys know what it is, but this is questionable. The guys probably lied. So ignore this; it means nothing.
--You did not ask for specific bevels for the base and the side. It would be good to know what they used, and in the future always ask for specific base and edge bevels when you get these tuned. So when you take the skis to the next shop, ask them to check and tell you what the current bevels are, and if they are consistent from tip to tail. They may be reluctant to do this, but press them. If the bevels aren't consistent, that could be a major problem. If they are, then no problem with consistency, but maybe you don't want those bevels. I doubt the bevels, unless they are really inconsistent, caused the problems you described.
--Typical bevels are 1º base and 2º edge bevels. But there are lots of other combinations. When you get these tuned again, discuss what two bevels will be best. They can change what the previous shop did, or repeat it. Trust the shop techs about what bevels to use, if you like the way they treat you, and remember what the bevels are so you can always ask for those degrees in the future.
--How the skis are sharpened matters. If the process leaves little "burrs" along the edges, they will rip your skin roughly when you rub your fingers along the edges. If you look closely with a magnifying glass, you will see the edges are bumpy. This should not be the case. They edges should be sharp but smooth. The skis will grip too much if there are burrs, and could send you straight across the trail if you're in the back seat. Ask the shop you take them to if there are burrs along the edges. If yes, that could be your problem. If not, look elsewhere for the cause of the skis' misbehavior.
--Tuning to "factory specs" has nothing to do with "detuning." "Detuning" means someone, after sharpening the skis from tip to tail, unsharpened the tip and tail. How far they ran a tool along those edges towards the middle of the skis to remove the sharpness matters. Most shops will detune unless you tell them not to. People who ski on hard snow and know how to carve like the edges sharp all the way to the ends of the skis. But many people don't like that because the skis grip when they don't expect them to, so detuning works for them. Unsharp edges, which were detuned too far, will not grip. So a shop can detune too much, or too little. I'm guessing (guessing) you would benefit from a bit of detuning, just the right amount. Too much detuning would cause the skis to not grip well on hard snow.
--The black base has a structure applied to it, a pattern of tiny indents put in it, to help it glide. The wrong structure can make a ski refuse to turn. As in REFUSE to turn. Ask the new shop to look at the structure and tell you if there's a problem with it. If they say yes, then there's your problem.
There may be other things that could have gone wrong with that tune. Others here may be able to alert you to more potential problems. Tuning is complicated.
Finding out what went wrong when you take it in to the next place will leave you fully confident that the situation can be brought under your control in the future. I'd ask all those questions and take notes as they answer.
So sorry to hear of this mistreatment you got. So typical.
