Affects Version/s: 1.12.0
Fix Version/s: None
Console: Xbox One
OS Version: 10.0.18362.4050
Minecraft Version: 1.12.0
Issues: Black boxes ringing player character, invisible mobs, unable to enter third person mode
Firsts, there is a ring of large black boxes wrapping above the character's head. Looking in one direction, the boxes are solid black, and in the direction they pulse purple in a similar way to enchanted items, except the color is uniform. The boxes seem fixed to the camera and move with the character, even bobbing up and down with the simulated head bob while walking. The ring stays oriented in the same direction constantly, but looking at them at certain angles up and down cause them to temporarily disappear.
Second, most mobs have disappeared. The only indication that a mob is in any given spot is the shadow circle and any particle effects, like the purple particles around endermen, they typically cast when the game functions as normal. (Unfortunately the only enderman I found in the world teleported away before I could get a screenshot.) They still produce sound, can be collided with, and will attack and deal damage (if the mob is hostile).
Third, the third person perspective seems to no longer work. Pressing the button to enter third person view doesn't change perspective.
All issues persist across worlds.