I was stacking armor stands in a single location on a bedrock realm when I noticed that upon relogging the armor stands were gone. No breaking animation is played or item visible, they are just gone. However, I noticed that a few times the items would somehow get into the hopper in the top left of the picture and end up in my storage system, so maybe it's some strange hitbox bug? I'm sorry I can't come up with a more comprehensive step-by-step guide on how to replicate this bug because I'm very confused as to what is causing it.

UPDATE: I tried to place some and unload the chunk by walking far away and returning, and they destroyed themselves. The item drops were still there, though.