Relates to MCPE-239735, MCPE-239737 and MCPE-243593.
If an enderman is holding a chest, its arms will correctly extend outward to indicate this, but the chest itself will be completely impossible to see, unlike most blocks.
To reproduce:
spawn an enderman
run this command: /replaceitem entity @e[type=enderman] slot.weapon.mainhand 0 chest
To compare in Java Edition (where we see the correct behaviour), use this command: /summon minecraft:enderman ~ ~ ~ {NoAI:1,carriedBlockState:{id:"chest"}}
Expected results: an enderman holding a chest.
Actual results: an enderman holding nothing.
Thank you for helping us improve Minecraft! We saved your files: