The Bug:
Entities with passengers can rotate their heads at any angle without their bodies moving with them.
Steps to Reproduce:
Summon a husk riding a spider by using the command provided below.
/summon minecraft:spider ~ ~ ~ {Passengers:[{id:"minecraft:husk"}]}
Walk around the back of the spider and wait for it to eventually look in your direction.
Take note as to whether or not entities with passengers can rotate their heads at any angle without their bodies moving with them.
Observed Behavior:
Entities can rotate their heads at any angle.
Expected Behavior:
Entities would not be able to rotate their heads at any angle without their bodies moving with them.
Can confirm this behavior in 21w42a. Here are some extra details regarding this problem.
The Bug:
Entities with passengers riding them can rotate their heads without their bodies moving with them.
Steps to Reproduce:
Summon any entity that has a passenger, for example, a husk riding a spider.
Walk around the back of the spider and wait for it to eventually look in your direction.
Take note as to whether or not entities with passengers riding them can rotate their heads without their bodies moving with them.
Observed Behavior:
Entities with passengers riding them can rotate their heads without their bodies moving with them.
Expected Behavior:
Entities with passengers riding them would not be able to rotate their heads without their bodies moving with them.