HC__skierI had some skis custom built by I D R I S and they warped. (pine core, oak sidewalls - very light though)
The Afterbangs are very "damp" skis, very low energy, and quite heavy. They also lose any pop they had to start with after a season or so of hard riding. They were made with durability being the number one priority, and they did that well.
They are hopeless to carve on.
Like a skateboard deck and a drum shell, they are made from plywood.
The warping on your skis will be due to their short length, relatively large tip and tail and quite deep sidecut. The torsional forces from the tip and tail essentially always trying to return to flat while you are torqueing the middle of the ski laterally (putting the ski on edge) have to be dispersed over a smaller distance than conventional skis.
Assuming they were built with a relatively conventional construction, the core will be made from vertically laminated strips of wood and the warping will be due to very low scale delamination and vertical displacement of these strips relative to one another. It is a tricky one to combat - if you go to a horizontal laminate or cross-ply (aka plywood) you lose longitudinal energy/stiffness.
Personally I would be looking into using a couple of layers of metal (titanal) in the construction, above and below the wood core, as this will help the wood maintain it's position - even if it's an H pattern like the Line Prophet used.
But this is massively off-topic.