Most of the coding I do is in Excel VBA (for work), but I've been getting better at reading and interpreting FSO code, and I think I may have a good theory on a fix.
In modelread.cpp, line 1264, part of an if statement, checks to see if the modder has specified a sub-object as one of a series of possible subobjects types for the purpose of rotation. It does not include "$look_at:" in the list. Look_at animations are never enabled. (pm->submodel[n].can_move = true; is the statement I'm looking for) Though, it could be a type that doesn't need to be enabled.
My skill is limited, but it looks like coder oversight since look_at is such a special case model animation, and the coder probably didn't know about it.
Though, if it were added to the list, it would need to be tested in case there are other things wrong with the animation type due to further revision differences. And enabling it could have effects on other things. *mumbles to self* I totally need to learn how to make a custom build. *ends mumbling*