When you open a world, entities can sometimes face the wrong direction
Environment
Windows 11
Linked issues
relates to 4
MC-272577
Summoning any entity with rotation causes it to be rotated incorrectly
Resolved
MC-93533
Armor stands face wrong direction for an instant after being placed
Resolved
MC-72774
Entities render incorrectly on the first frame after being summoned
Resolved
MC-88181
Entity NBT isn't always synchronized with clients immediately, rendering the entity incorrect for a brief moment
Resolved
Can confirm in 1.21 pre-release 2. Easily seen if you place an armor stand and relog. This is, to put it mildly, catastrophic to any map or datapack that uses display entities in any capacity.