The hilt of sword got through the hand of small armor stands.

How to reproduce

1. Use the following command to summon a normal armor stand

   /summon ArmorStand ~ ~-0.5 ~ {Pose:{RightArm:[-15f,135f,-90f]},HandItems:[{id:"stone",Count:1b},{}],ShowArms:1b,NoGravity:1b}
   

   The stone block should be displayed horizontally

2. Use the following command to spawn a small armor stand with the same pose

   /summon ArmorStand ~ ~0.5 ~ {Pose:{RightArm:[-15f,135f,-90f]},HandItems:[{id:"stone",Count:1b},{}],ShowArms:1b,NoGravity:1b,Small:1b}
   

   The stone block is not displayed horizontally, however if you decrease the second RightArm value by 20, it gets displayed horizontally as well:

   /summon ArmorStand ~ ~0.5 ~ {Pose:{RightArm:[-15f,115f,-90f]},HandItems:[{id:"stone",Count:1b},{}],ShowArms:1b,NoGravity:1b,Small:1b}