I played the mission 35 - Moonlight Pass against 2 wolves when it happened!
I built up a trebuchet to attack the right wolve. Afterwards I sent the engeneers out of it and they became halftransparent enemy forces! Just watch it. Its quite fun
.:::Now I put a picture in the zip how it looks like on my screen:::.
Well, it's not the first time I see this "bug", if we can call this a bug... Well, I did it all the time, and the explanation is quite simple. In fact, you make your trebuchet really close to an obstacle (here, it's a partition, but it could be also something like a woodcutter). So, what happens when you do this is that, when you remove your engineers from the trebuchet, they can disappear. And, if, at the very same time someone on the map make troops, the troops remplace the engineers with the troops. So, we can't see it('s an incredible bug, just one of the many over bugs which are in the game. If you want to see many other bugs, just asking me ; I can show you quite impressive bug which are very sometimes incredible. I make 2 as rating because you take the save at the good moment ;)