Tamper Proof Keystone in Atlas Tree

Hello, I think I may have found a bug.

I'm in the Port Map, Level 16, standing next to a Normal Blacksmith Strongbox.

The issue is I have "Tamper Proof" allocated in the passive tree which I think means it should be Corrupted and Rare?

Thank you for the awesome expansion and league, very fun!

Edit: It just happened again in the same map except it was a Rare Strongbox but not corrupted.

I can confirm the issue. Occured several times already, here is the latest occurrence.
Bug id #324 666 137

Edit: Nevermind, i forgot i was in a Kirac's mission, cf. quest tracker on the right. Might be the case for the others occurrences, i'll be more careful.