It uses different links now
Old https://www.humblebundle.com/store/p/blitzkrieg-anthology_storefront
New https://www.humblebundle.com/store/blitzkrieg-anthology
Some get redirected properly, but not all as above example Blitzkrieg, Removing the /p/ and _storefront should do the trick.
Topic on User talk:Garrett
Well spotted, I've fixed it now.
This change on their end has also affected some game IDs (e.g. Oceanhorn: Monster of Uncharted Seas has changed from oceanhorn
to ceanhorn-monster-of-uncharted-seas
), so some store links will now be broken.
I see. Will check any links I'll come across to.