Related to MC-57861.
Particles appear to tilt sideways when sleeping in a bed
Usually, particles render like they are facing at the player, similar to the way ender pearls, ender eyes, snowballs, XPBottles, Thrown Potions, et cetera. At a time around when the guardians came out, projectiles looked 2D (MC-57861). This was fixed but this issue still exists.

Steps to reproduce:
1. Place a portal, torches, redstone torches, drink a potion, (do anything that makes particles, but mobeffect and the flame particles work best).
2. Sleep in a bed. If the particles aren't sideways, click "Leave Bed" and change your rot and get in it again.