Trial Chamber Chests have no loot

I was playing Minecraft today and checking out the Trial Chambers, and I saw a lot of chests around the place. I though they could have some valuable loot, but when I opened the chests they had no loot. All of them for some reason didn't have any loot. I even generated a new world to see if the chest in the Trial Chambers had loot, and they didn't (See attached GIF).