I understand that this frustrating glitch has still not been solved for 1.3.

I have a little more to add which may help, though you probably already know about it.

The black patches appear on the Rebel uniforms on Endor only when viewed at long range through a sniper scope, but the patches on the Imperial uniforms which you can see in normal view on Rhen Var disappear when viewed through a sniper scope.

Mmm... vanilla!