Well I've downloaded yhese characters. This "bug" have an easy solution:
The problem on these characters is this code on the statedef -3:
type = helper
trigger1 = NumHelper(100000) = 0
trigger1 = NumPartner = 0
trigger1 = enemy,NumPartner = 0
name = "systemhelper"
id = 100000
pos = 0,0
postype = p1
stateno = 100000
helpertype = normal
ownpal = 1
keyctrl = 0
On every character the creator didn't set an state helper 100000. And since this helper programation does not exist you will always see 2 characters instead of one only. Just put a ; before the code description [state system]. This will solve your problem and lock this fake helper effect. It will be like this:
Why not delete the whole code? Because I, and probaly you too, do not know what it really do. Here the characters did their job without any bug. But since this is part of the character is best to leave it there and do not risk to delete the whole code. It's unnecessary.
Problem solved. Have a nice Mugen play!