Which models are you referring to? As far as I am aware there are no texture glitches with any of the StarCraft 2 campaign models of classic units. Are you referring to custom user-made models by any chance?
I've noticed some texture problems with the Sunken Colony in the Mass Recall mod. Even the new model by Blizzard seems to have adopted these problems, so I don't think the fault is in the model, but in the actor.