Small armor stands display items differently than normal ones

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}