Kevin Posey

Confirmed for 1.13

Guardian hitboxes are hilariously bad if the pitch is below/above about -40/40. I added an image (guardian_hitbox.png) with a guardian and elder guardian at pitch -75 and 75 for demonstration. The guardians render completely outside their actual hitboxes.

/summon elder_guardian ~ ~ ~ {NoAI:true,Rotation:[0f,75f]}

Seems to have fixed itself with a server restart.