For some reason not every game at 100% of seems to have a Claim button
Developers can decide whether or not someone can permanently own their game during a promotion, or just download the current version. For example, maybe they have updates in mind and they’d prefer people who get the current version for free later decide to buy the game to support it. If you “claim” a game then you’ll get all future versions and it will be added to your library of things you own.