When I apply effect "Haste" with amplifier from 1 to 3, my right hand swings and that's normal.
But things go worse when I start with amp greater than 4. Then my right hand no longer swings but it has an "up and down" hand movement.
And when I apply the effect with amp greater than 6 the hand just simply freeze. Completely no animation.
This bug has already existed in a couple of beta versions, including 20w22a and 1.16 pre-1.
Related issues
Comments

Duplicate of MC-10755 - effect levels that are not possible in regular gameplay are not supported.