I'm seeing a lot of complaints about glitchy characters that make a copy of themselves. I think it's mainly a problem that's introduced when an old MK character is put into a Season 2 game. I found a fix for this with Shin Scorpion. It had to do with the coding for blood helpers. Here's what I did.

I opened "Special_Moves.st" (usually it's "sp.st"). I searched for "blood" and found this:

[State 2, Roundhouseblood]
type = Helper
trigger1 = movehit
stateno = 7300
pos = 0,-110
postype = p2
persistent = 0
ignorehitpause = 1

I changed "stateno = 7300" to "stateno = 28". Sometimes I found one with "stateno = 7302". This also needs to be changed. It can be changed to anything from 27 to 31 depending on the amount of blood that is appropriate. I found that there was still one last duplication glitch. I fixed it by removing this:

[State 0, Helper]
type = Helper
trigger1 = anim = 2013 && movehit
helpertype = normal
stateno = 299
postype = p1
ignorehitpause = 1
persistent = 0

I don't know what it was supposed to do, so I just commented it out for now.