Just had a play with my system and the fps and zombie combination is fine. Some how this must have been missed off an update. We will make sure it gets in the next update.
I will be organising the characters and other game system assets into a new Game Objects tool box so it will be easier to find mechanics that are related to your game design.
I will have a bit more of a play just to see if there is anything wrong and then I will post a copy for you here.