It is possible to loot the same vault multiple times by repeatedly exporting the world with the "Clear player data" option

Steps to reproduce:

1. Create a new world
2. Craft and place down a couple of chests
3. Find a trial chamber
4. Obtain at least 2 (ominous) trial keys
5. Unlock a(n) (ominous) vault
6. Move all of your inventory contents into a chest/multiple chests, including the loot you received from the (ominous) vault
7. Export the world with the "Clear player data" option enabled
8. Import the freshly exported world
9. Locate the chests
10. Retrieve your items
11. Unlock the same vault you already unlocked previously

Observed result:
You can unlock the vault again (every time you export and re-import the world with the "Clear player data" option enabled).

Expected result:
You are not able to unlock the vault again.

Notes:
This appears to be caused by the ~local_player's UniqueID value being changed every time the world is exported with the "Clear player data" option; the UniqueID value decreases every export by -4294967296, and due to this the vault perceives the player as a new one every time the world is exported with that option enabled.