When playing a world in 1.8.1 Pre-2, mobs tend to glitch out and turn invisible. (Pictures 2-4) This also affects the player model as well. (Picture 1) This was recorded as a YouTube video for a survival series so I have footage on my channel, CorpseEntertainment12, under the title Oasis Survival episode 6. Reloading the world in release 1.8 fixes the issue.

NOTE: I've searched all mob entries on JIRA, so if this is a duplicate, I apologize.

How to create:
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This was a world that was a custom flatworld generated before 1.8. Any world generated in 1.8 or higher still has fixed mobs.
1. generate any world in previous versions of minecraft
2. load it up in 1.8.1 Pre-2.

NOTE: This glitch is unique as it only happens on occasion, and only affects certain mobs. I can't pinpoint the exact way to reproduce this bug and only have screens to prove it happened. If you are unable to recreate the bug, let me know.