There are now a number of new issues, in addition to the existing "nether chunks shift up and down or disappear totally" issue that's been around for months.

I don't know if these are related or not, so I'm not breaking them into separate tickets. I'll just list:

1. Axolotls and goats no longer spawn.
2. Blocks are slow to break into drops, often reappearing after breaking, and often several times.
3. Lava does not flow and does not hurt the player.
4. Chests take two clicks to open.
5. Sometimes double chests split into two small chests and you cannot interact with the contents until you break the chest and remake it.
6. Rails often don't connect to already placed rails, and then disappear minutes later.
7. Mobs freeze in place for 3 or so seconds at a time, and cannot be harmed when frozen.
8. Status effects like poison from witches last after the visual impact is gone (as in, hearts go back to red from yellow, but you still keep taking damage). Also the blue particles from night vision stay long after the potion has eorn off, as well as the sky staying 'tinted.'
9. Any placing of a block or other interaction (even just opening inventory or swapping hotbar contents) is laggy, including the audio effect associated with the action.