LOL, same thing happens in EAW or OP with legendary weapons officers. It can be a real pain, your ship can go pop just like that, before you even know what is happening... Or phasers that hit for damage at range 30... The problem is that connection issues in mission (host left message) can produce the same effect: known as "The double fire bug". Any mission scripts that used legendary weapons officers are gone now I believe...
Correct me if I'm wrong, but I do not recall legendary weapons officers allowing all weapons to be fired twice per turn in SFB, I think perhaps there was just a modifier to hit? Again, deviation from a well tested game seems to be the problem...