Affects Version/s: Minecraft 18w16a
Fix Version/s: None
Java 8 Update 161 (64-Bit)
GTX 1060 6GB
Intel i7-4790k @ 4.5 GHz
This is easy to replicate:
Make any new world - preferably creative - and then teleport to to edge of the world:
/tp @p 30000000 100 30000000
Then, use the following command to place a layer of sand in the air next to you:
/fill ~1 ~1 ~1 ~15 ~1 ~15 sand
...and watch them as they horrendously glitch out and go crazy until they land.
Also, I'm not 100% sure, but it does seem as if it takes them longer to reach the ground as well.