ViljaAH

This video is on version 1.21.10, this issue is very noticeable when firing at phantoms that are coming straight towards the player. The clip is from me dealing with this in survival, I might try to record a better reproduction later. The bow being used here has infinity, which might affect things.
This should be compared with MC-302221 which I believe is the same bug, because (1) the arrow bounces of a moving entity, and (2) the bug is not visual. The bug on this page specifies phantoms, but this also happens with other mobs, as seen in MC-302221. One of these bug reports should be marked as a duplicate of the other.

Contrast with: MC-102732 which in the innitial bug report description says it is a visual bug and/or a desync between client and server. The later videos however appear to show this bug.
These reports should be centralized on one issue, if they are the same or marked as duplicates if this is still the same bug as reported innitially in 2016.

I was able to reproduce this on version 1.21.10 with other entities as well, zombies and other mobs with similarly shaped hitboxes seem better suited for this, because their head or the top of their hitbox is at the height of the player. Shorter hitboxes seem to require player to be lower for the arrows to collide with the hitbox a similar way.

Wind charges and eggs also seem to have similarly odd behaviour, but especially with the latter the bug is harder to reproduce. Both stop in the air but do not bounce like arrows do. Both require the mobs to be moving and occur when attempting to hit near the top of the hitbox.