Some information

Note that this only occurs on occasion, and it relates to MC-194173.

The bug

Entity hitboxes (including the player's) occasionally shift upwards or sideways while picking up an item or an experience orb while facing to the north. I discorvered this while testing MC-194173, and I found this with endermen (but it likely occurs with other entities as well, but I haven't tested it). It usually only occurs with one (if any) entity within view, as you can see in the attached video.

How to reproduce:

1. Look to the north, facing some entities (the more entities, the more you are likely to see the bug)
2. Enable hitboxes
3. Drop an item in front of you (or an experience orb)
4. Pick the item or experience orb up
5. Notice that on occasion, entity hitboxes shift upwards (but not the entity itself) for a few frames.