I got that buff too. It was in the character effects pack because after removing the effects pack only and not the creaturepackhuman I was completely debuffed (no flies, lol) and was not displaying the "isinfected" symbol. If it weren't for the flies, I would happily watch my character turn I had the marvelous priviledge of watching a farmer turn, the experience was seamless and believable (very well done indeed).
I also noticed that with the effects pack activated, vanilla zombies make no guttural sounds when they spot you.
Contrary to what you say about turned zombies not attacking the player, the farmer once turned, did attack.