Not sure if this applies only to missiles or to all weapons
If I set missiles to hold fire unless given a target and then assign a target, they fire as expected. However, if after assigning a target I power the missiles off, cancel the target, and power them back on (still set to hold fire, and with the former target now canceled), they will continue firing for a brief period at the old, canceled target.
Not a serious issue, but it makes it difficult to control missile launchers.