I've had the issue as well. I'd changed mafia builds since I'd last sucessfully used it but when I used the old build I was still getting the issue. I *think* the issue might have been my ridiculously low HP. Using the script now as a level 17-18 SR, I have about 300hp and 200 base muscle unbuffed.
I'll hazard a guess that it calculates that I can't survive more than 1 turn because I can't kill them fast enough... but I see other people with higher HP/Level seem to have teh same issues.
Tried on builds 7555(used to work, I did my slimeling runs with this), 7590, 7594, and the latest compiled .exe. I;d give you a log but I dont know how.