With a recent update in drops, there’s a small error in the current OSC!
The error
The boss drop for the current One-Shot Challenges (with Numens as boss) gives Gems of Numens in rare cases.
This is due to the boss drop having a rare chance to be a Gem now, which didn’t happen when the OSC debuted.
The compensation
New Limited-Time Exchange available after Maintenance!
Available: 5/23 (Thu) after maintenance –> 5/27 (Mon) 11:59pm JST
For a short time you can exchange OSC Boss Gems back to the original cards! So you can turn a Numen back to non-Gem version, that seems like the compensation for their error.
Featured image source: @toba_ww