Well that was a long shot. It didn't look modified, and you have the sound of someone who's got the basics down. It's just that about 85% of the IE's I encounter myself are somehow weapon systems related. Or a biffed art.ini entry.
Same is sort-of true of allowing OccupyFire on armed buildings. The moment the troops enter, the Primary goes away. At a guess, the "occupy fire weapons" /become/ the primary. I never tried a Secondary to see if it was preserved. My hypothesis: maybe.