I have the same issue. This is not a case of chests re spawning loot after having been looted once, these are *randomly spawning chests* in the wilderness, accompanied by two guards from the Inquisition or an allied faction. They spawn as a sort of reward for securing a wilderness area. However, it isn't much of a reward if they are always empty!
I was able to loot the first two I think, both in the Storm Coast area, then never again. They pop up all over the place, in all the different wilderness areas (I have claimed everything) but It can never interact with them. It's like the guards are taunting me, "Here's some LOOT for you...LOL!!"
I think this is just a bugged mechanic, hence why people don't seem to understand it. Please fix this (or if there is something we can do to get it working again, please tell us); it was a good idea and would be a great way to reward players who have already looted the standard chests etc. in an area but still want to play. This kind of thing will be even more important once you start coming out with the *DLC* and your most loyal players have already been through the game by then.
Conversely, if it remains as it is, we will have a constant reminder in our faces, "This game is bugged...this game is bugged...this game is bugged..."