Attempted fix on the enemy Little Bird.
 

I always thought there was something wrong with the enemy Little Bird's main rotor. My latest waste of time was to check it out and try something.

My best guess is there are two ways to deal with this: Edit the EAH6C.3di so that the irtrblrh.dds is no longer tiled on the rotor polygons (slightly beyond my skill set, today), or redraw the alpha on the irtrblrh.dds and remove the artifacts (a plan so in my wheelhouse, I'm adding it to the sign on the door).

See the attachments for the results.