Typically, when an entity is sleeping, it's rotated by 90° to depict lying down. However, spiders, cave spiders, silverfish, and endermites differ—they're rotated by 180° instead. This divergence likely stems from their death animation, where they rotate by 180°, unlike other entities that rotate by 90°.

Reproduction steps

1. /time set midnight

1. Position a bed with its foot at coordinates 0 -60 18

2. /summon minecraft:spider ~ ~ ~ {SleepingX:-1,SleepingY:-60,SleepingZ:18}

   (You have the flexibility to modify the command coordinates if you've positioned the bed elsewhere.)

You can modify the spider in the command to a cave spider, silverfish, or endermite.

Observed: The mob is rotated by 180°.
Expected: The mob should be rotated by 90°.