This is the first time I was actually able to see what was going on. I was riding my horse, exploring the world for a Stronghold, when an invisible barrier blocked my path. It wasn't infinite, as often times I could ride around it. But when I got tired of it, I decided to do a bit of testing to figure out what was going on. I shot a few arrows at the cow inside the barrier, and they stopped in midair, as you can see. However, the model updated to show it had been hit.

I left the game, waited a few minutes, and rejoined. It seemed to have fixed it. I kept riding on, until I got to the edge of the forest, where I suddenly ran into the next major barrier. Literally.
I rode my horse against the barrier so I could figure out where it would end, all while being chased by 3 Phantoms. Upon riding into the barrier while my horse was in the water, it froze and started twitching about. After getting off to hopefully save myself from this Twilight Zone encounter, the Phantoms dived at me. Upon diving, they got frozen as well. Yet, for some odd reason, their actually positions were fine. Only the models were frozen. I found this out by being repeatedly smacked by invisible Phantoms. Fun, isn't it?

I assume it turned daytime, as their models turned red from burning damage, and their screeches sounded about. All the while, the surroundings from my perspective stayed the same, while the world around me shifted.

Hope this gets fixed soon. It'd be a shame to be stuck in time.