I had that problem like this with Plasma Armor before, but not in RoM.
Or if it was, it would have been a very early version of it, since it was a loooong time ago. Back when the Plasma Armor model was a new and exciting thing.
You could try reinstalling the mod. The texture is fine on mine, at least. (Just checked)
In my last game I inexplicably crashed every time I tried to build a Fighter, which had a pink square for a button, even after I changed the button texture itself. Could upgrade fine to them from early fighters. So my plans for expanding my airforce were stalled until jet engines.
Guess my scientists couldn't quite figure out a better prop plane.
Point is, weird glitches like that just happen sometimes. It's one of the downsides of putting in stuff from a dozen artists, all doing things a bit differently.