The bug

Slimes and magma cubes can't control some rideables mobs.

Steps to reproduce

• Use the following command:

  /summon minecraft:camel ~ ~ ~ {SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:horse ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:donkey ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:mule ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:skeleton_horse ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:zombie_horse ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b},Passengers:[{id:slime}]}

  /summon minecraft:llama ~ ~ ~ {Tame:1b,Passengers:[{id:slime}]}

  /summon minecraft:trader_llama ~ ~ ~ {Tame:1b,Passengers:[{id:slime}]}

  /summon minecraft:pig ~ ~ ~ {Saddle:1b,Passengers:[{id:slime}]}

  /summon minecraft:strider ~ ~ ~ {Saddle:1b,Passengers:[{id:slime}]}

  /summon minecraft:horse ~ ~ ~ {Tame:1b,Passengers:[{id:magma_cube}]}

• Notice that the slimes or magma cubes have no control over the rideables mobs.

All affected rideables mobs:

1. Camel
2. Horse
3. Donkey
4. Mule
5. Skeleton horse
6. Zombie horse
7. Llama
8. Trader llama
9. Pig
10. Strider