It appears that the spawn rates of mobs and growth rates of trees and wheat and other things have been severely slowed. I looked up the default tick speed of Minecraft and I found that it should be 20, but if I go into the settings of any world they all say 1. I can't just change it to 20 either as I want to play through the world on survival and I want to get achievements. I don't know if this is a new thing or a bug but, thought I would share.