The completion condition for Cracking the Vault seems strange - my first Strongbox spawned, with 106 coins at level 1 (as per the new production rules for them. After destroying it a few times, I noticed I got completion credit despite the box only being level 5 or 6.
At first, I thought that the trigger was based on the coins I received (eg the game wasn't checking "level"), but looking at the credit for Lockbreaker, it says I have 16/50 levels, even though my only box now has level 9. Perhaps it's checking dungeons or unclaimed hexes?