The only mini mods I have installed which touches models and animations are Darth Stalin's 1.1 Gallic Helm Romani mod, Fanatic’s First Cohort/Phalanx/Elephant/Chariot minimod and the added Aquilifer unit , none of which - although I´m no authority on the matter - interferes with most of the units affected, the polybian legionnaires for example.

I ( always ) have an extra clean EB install which I will try these three out on one by one, but I might add that I have done so in the past without ever seeing anything resembling this.
I´ve also done a reinstall but with the same three mini mods applied together like before when the error occured and I played 20 years and a few test custom battles yesterday without any graphical problems with any units whatsoever - even though it may return as it have before.