On further investigation, when the defensive aid system defeated a missile, the to-hit chance was reduced to 0. Because, miss.
However, further on down the code there was a guard check that made sure the to-hit was in the 1-99% range. So the zero chance was upped by the guard code to 1%...
I have added a flag for a missile defeat now, and the proper 0% to-hit chance is being carried forwards.
In addition if that flag is set then the target does
not make a futile dodge attempt on an already defeated missile, it jumps over the dodge block of code completely.
But that
seems to have been your problem - a 1% minimum to-hit chance was applied even after the "CIWS/VIRSS defeats missile" message. If the target had CIWS then the MG noise was played for CIWS system being fired. Your tank that "defeated" the missile fell to the 1% minimum to-hit chance that is now sorted for the case of defeated missiles.