Hi,
Automatic Transmission Fluid is what I refill my hydraulic reservoir with, and that is in contact with the cylinders and seals all the time when the lifts are retracted.
A little ATF on the cylinders should help. How long have the lifts been down? Do you bring them up every once in a while, or is this a thing that happened while spending long term someplace?
I think that the company does not want WD 40 on the cylinders because it might react with whatever the seal is made from. But that is just a guess.
Good luck,
Fred.