Okie so after going over the coding with pyth we have determined the cause of this issue, it is in fact not an issue at all.
What is going on here is there are two separate missile launched at the same exact time, because of this when the two missiles collide with the target they both hit at the same time, instead of two red numbers coming up to display the damage dealt it LOOKS like one red number, in fact the second number is hidden behind the first because they are exactly the same you cant actually distinguish the two from each other.
My suggestion is next time you use cursed waves check the actual HP of the target being hit and the damage being dealt should differ then the actual red numbers popping up.