You will gain the feat the same way as if it was a reward.

Resolution: On page 9 of the Guide, in After the Scenario, under Earn Rewards, remove the last paragraph. Add a new section to the Guide with the following text:

Gaining Specific Feats
When playing adventures published prior to season 6, it’s possible for characters to specifically gain skill feats, power feats, and card feats rather than hero points. The first time you specifically gain each of these types of feat, increase your maximum number of feats of that type to your Tier + 1 before gaining that feat. Each subsequent time you would specifically gain the same type of feat, you instead get a hero point that you may immediately spend on a feat of that type, but the maximum number of feats of that type is not further increased.