Originally posted by Ammikaameri:

You need to make sure your inventory is empty when you first access the grave. It will automatically loot all the items.

There is also the issue that you might need to equip the strength belt to be able to get all your stuff. The game won't automatically recover all your stuff if it will make you encumbered even if you have the inventory room for it all.

I've gotten killed several times trying to recover my gear because when I was originally killed I was trying to carry a load of iron out of a swamp. Without the belt equipped the game wouldn't let me to a grab and dash on my marker. and while I was trying to just grab the belt and armor I would get killed again.

I keep a second belt on hand now for those occasions .