So there is some kind of visual bug to Armorstands, basically when there is Enchanted Armor visible on a Armorstand and looking inside, it is not showing it's glowing enchant.

Some of the other Armors that is also visible on a Armorstand aren't either rendered or invisible, this is more noticeable to helmets. This might be only applied to the World Border nearby (seen below).

Steps to reproduce:
1. Load up a world
2. Place an armorstand
3. Place any armor on there or all the same, including enchanted armor
4. Look inside of the armorstand closely

Screenshots:
Comparisons of Diamond Armor and Enchanted Diamond Armor.

Comparisons of Gold Armor and Enchanted Gold Armor, notice the Gold Armor is slightly invisible on the inside.