I won this giveaway, successfully activated it 3 weeks ago. But today I've got an announcement from Steam:

"Spec Ops The Line Retail
Your recent Product code activation has been revoked due to a problem processing payment for this item. The games associated with this product code can no longer be played as a result. This could be due a problem with the payment methods you used to acquire this item from a third-party seller; or a problem with how the third-party seller acquired the Product code."

Currently the Humble Bundle link says "the order is cancelled"/"Unknown gift" instead of usual "The gift is already redeemed".

The game is actually removed from my account at the moment.