The sign up bonus on the Discover it card and Discover it secured is matched cashback for the first year. Capital One has acquired Discover and is integrating these cards across and part of that is giving them access to Capital One offers. Interestingly it seems that Capital One offers are triggering the first year cashback match.
This only applies to Capital One offers and not Capital One shopping (more information on the difference here). There are a lot of good Capital One offers (view them here) and doubling them would make a lot of them profitable as well. I wouldn’t be surprised if Capital One changes this at some stage so they don’t get matched.
