Summoning rotated armor stand riding rotated horse causes armor stand to be incorrectly rotated

When I summoned an armor stand riding a horse and used the Rotation tag, it didn't work for the horse.

/summon horse ~ ~ ~ {Tame:1b,NoAI:1b,Passengers:[{id:armor_stand,Rotation:[180f,0f]}],Rotation:[180f,0f]}

The horse just ignores the Rotation tag.
The same result:

/summon horse ~ ~ ~ {Tame:1b,NoAI:1b,Passengers:[{id:armor_stand}]}

When you try to rotate the horse manually, with the following command the horse rotates 180° and the armor stand rotates something like 100°

/tp @e[type=horse] ~ ~ ~ ~180 ~