I believe that I have found one potential solution.
From the attached image, the original ViCond specified only ONE
specific unit as eligible to fulfill the ViCond and you needed to destroy 10 such units. Obviously, this is an impossibility .
The solution I propose is to replace the ViCond from specifying a particular unit with a ViCond that looks for a Class of ships to destroy, in this case, the Armed Junk.
I have tested this ViCond 3 times and it has tripped correctly on every occasion.
I do not believe that this particular ANW ViCond is a problem with the Game Engine. However, I cannot be certain since you did report that the ViCond evaluated properly on one of your test runs. The ViCond
Never triggered correctly during any of my game sessions so there may be some truth to your claim that the ANW ViConds are 'twitchy', but I am unable to confirm your findings.
The scenario has been sent and I hope that it works for you.
