Steps to reproduce:

1. Summon a mob with NoAI:1b.
2. Position it on the exact middle of a block.
3. Position yourself also on the exact middle of a block a few blocks in a straight line away from the mob.
4. Rotate the mob to face you using /rotate, for example:

   /rotate @n[type=husk] facing entity @p
   

5. Press F3+B to make hitboxes visible.
6. Note the mob's line of sight is misaligned.
7. Retrieve the mob's rotation using /data, for example:

   /data get entity @n[type=husk] Rotation
   

8. Note that the first value is offset by a very small margin. This is likely caused by inaccuracies in the formula used in /rotate; the mob apparently rounds the result up, causing its rotation to visibly mismatch.