The active bounty community advertisement seems to be broken, displaying 2 bounty for a total of 550 rep, when the featured page shows 4 for a total of 700 rep
It looks like this is outside the scope of our site. This image is not owned by us but a third party (I think https://github.com/51cards/Stack-Exchange-Bounty-Ad).
As far as why the information is wrong, I would blame caching. There was a point when this information was true. There were two bounties worth 550. Then two more bounties were added bringing it to 700. The stale information just needed to age out of whatever cache it was in.