I tested the main Fs2 Campaign, and it results there are several scripting bugs.
It appears especially when the colossus is on station.
The first time we met him during the evacuation of Enif Station, the Colossus seems to be out of range. It can't use his beam cannon towards a Deimos class. I've to just autodestruct myself to pass the mission.
Another bug, in the final battle before we go to Vasudans Head Quarter, the Colossus arrived near to the knossos, but unfortunately, he is too far from the battlefield. So, he can't open fire.
Well, i don't know if the fs2 files are messing up in this 3.6.7. I hope there will be a fix.