This error occurs in the Nether with the new creature Strider, where we have the chance to catch one of them "bug" (I don't know if he spawns like that or if we bug him). And then it starts to float off the ground. In the print a friend of mine shows exactly that. Another thing is that the Strider does not reproduce floor animation if another player is on it, if it is the player itself it does the normal animation.

This bug occur on 20w13a and 20w13b

sorry for bad english

print:
https://imgur.com/a/8crwAZv