There is an unknown cooldown period after exiting a delve or dungeon that prevents the new area having mostly filled containers.
You’ll see barrels, bags, crates and other storage containers mostly “<Empty>”
If you were on cooldown, most of the containers in the new dungeon will be empty except chests and heavy sacks.
It is unknown how long the cooldown is – probably 15 minutes.
One way I found working is to quit the game entirely and start it up about 10 minutes later.