Bug:
1. Completionist achievement was not triggered when all stamps were collected.
Fix:
1. Players who have already unlocked all 10 stamps will automatically get stamp when the game is updated.
Achievement Fix
Source: Steam Community (opens in a new tab)
Build and release context
Steam update times within 24 hours of this post. Matching dates do not confirm which build it describes.
Build 10916449 · public branch
Steam updated · First observed