I've been using Grim Reaper Eddie exclusively as my Eddie since yesterday's update. First, it appeared that his Slash skill attack never procs an additional attack. After a while, I noticed that about as often as it used to proc an aditional attack, GRE instead takes about 6k in damage. It doesn't seem to matter what enemy I'm attacking, but I noticed it while farming Battlefield/Madness, first fight "Shell Shocked". I've since tried other battles with the same conclusion: it looks like the additional attack procs, but instead of enemies it hits himself.