When mounting mobs such as horses, donkeys, mules, skeleton horses, zombie horses, llamas, or camels, your facing direction adjusts to match the rotation of the mounted mob, rotating you towards the front. Likewise, when mounting a boat, your rotation shifts to face the front. However, this behavior does not occur when mounting pigs or striders.

steps to reproduce

1. /summon minecraft:pig ~ ~ ~ {Saddle:1b,NoAI:1b}

2. Mount the pig

3. /summon minecraft:strider ~ ~ ~ {Saddle:1b,NoAI:1b}

4. Mount the strider

Observed: When mounting pigs or striders, your rotation remains unaltered, unlike when mounting other rideable mobs or boats.
Expected: When mounting pigs or striders, your rotation should adjust accordingly so that you face towards the front of the pig or strider, similar to other rideable mobs and boats.