Same happened to me, traded gift link with a guy, now its removed due to invalid purchase. :S

Edit: The guy i traded with turns out scammed everyone with WB bundle... http://www.steamtrades.com/user/Jacqhues/

"from a trusted source", seems not so trusted...

sorry, it was part of the hb cc fraud.

I bought mine and its still in mine.

GOD DAMMIT

It's not like you lost anything so just pretend you never got gifted it.

"from a trusted source"
Muhahaha... Not anymore.

Check the forum, like many people you bought it from a scammer. Nothing was wrong with the bundle, but it was bought with credit card fraud. Read the very first question in Humble Bundle Support page:

Why did my game disappear from my Steam library?

We recently deactivated several thousand orders that were found to be purchased fraudulently from Humble Bundle. Any games that had been redeemed on Steam that came from one of these fraudulent orders have been revoked and will disappear from the user's Steam library.

Please do not purchase anything from a third party that is from Humble Bundle as we can not guarantee that it has been purchased through legitimate means and may get deactivated as a result.

If you feel your purchase has been incorrectly flagged as fraud and lost your games as a result, please contact us using this email form so we can investigate immediately.

see here

You either:

• got it from someone who used stolen credit card info to acquire it
• got it from a middleman who got it from someone else who used stolen credit card info to acquire it
• or used stolen credit card info yourself to acquire it