For DISPLAY projectiles, bulletBillboard=CENTER does not work, always behaves like bulletBillboard=FIXED.
Title. Can be tested with any projectile with
bulletType=DISPLAY;material=STONE;bulletBillboard=CENTER
What should happen: the projectile display should orient to face towards the player, like how an ender pearl or snowball would What happens: The projectile is fixed.
Also does not work with HORIZONTAL or VERTICAL. https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/entity/Display.Billboard.html