It would seem there is a slight spam glitch when you are at negative karma and have it locked then kill something that would normally reward you with positive karma.
Everytime i kill something that normally would raise my karma, i get a:
"You cannot perform negative acts on your target." message.
I'm guessing that is the issue. It could also be that since i am now wearing a few pieces of crusaider and tainted gear that perhaps, upon monster death, a item is trying to give me karma and fails since its locked. Not sure it would be this since its the tainted gorget i have and that one tries to drain karma from me so that should be fine.
Eitherway, its very spammy