Not a bug, they added tall grass.
If you were using the ingame shaders or a texture pack, it could be because of those, but I have also experienced the status bars turning completely white.
Umm.......
This has also happened to me, and I'm assuming it has to do with the render distance bugs.
Not a bug.
When you go into water, it forces you off the horse or donkey. If you were in a large body of water, it probably drowned.