When I placed lava and walked into it(in creative) I got an animation but it looked nothing like fire but rather it looked like an opaque white block in your face. Also it is the same when sheep are on fire. I have not tested it with other animals. I then re logged and it gave me a real fire animation. I don't know if this was a one time glitch or if it is even reproducible but it happened. Didn't think to take any screenshots. It could be that since I just updated then created this world that is hand't loaded the files correctly.