A similar issue to MC-268986, previously labeled as incomplete, related to MC-162943. When riding a horse, donkey, mule, zombie horse, or skeleton horse and ascending one block, a smooth camera transition used to mitigate the abruptness. However, this functionality was disrupted in version 1.9, where the animation was accelerated. Upon setting the tick rate to 1, it became evident that the animation seemingly lasts only 1 tick in newer versions. Now the animation is very harsh.

There are already comparison videos from MC-268986:

• https://bugs.mojang.com/secure/attachment/563062/SluggishDonkeyAnimation_1.8.9_VideoDemo.mp4
• https://bugs.mojang.com/secure/attachment/563065/SluggishHorseAnimation_1.8.9_VideoDemo.mp4
• https://bugs.mojang.com/secure/attachment/563065/SluggishHorseAnimation_1.8.9_VideoDemo.mp4
• https://bugs.mojang.com/secure/attachment/563063/SwiftHorseAnimation_24w09a_VideoDemo.mp4

Steps to reproduce

1. Start version 1.8.9
2. Summon a mule (Opting for a mule is preferable as they are slower than horses, which enables a clearer distinction to be observed)

   /summon EntityHorse ~ ~1 ~ {PersistenceRequired:1,Tame:1,SaddleItem:{id:saddle,Count:1},Type:2}

3. Ride it upstairs
4. Examine the animation closely!
5. Start the newest version
6. Summon a mule

   /summon mule ~ ~ ~ {SaddleItem:{id:saddle,Count:1},Tame:1}

7. Repeat steps 1-5

Observed: The animation appears rougher compared to pre-1.9.
Expected: The animation should retain its previous smoothness from before 1.9.