There could be other reasons as to why the team chose to extend the bounty. I guess the tokensale is still ongoing and the service of bounty hunters are needed. The issue of extending duration of bounty is more like a norm, because things don't always go according to the plan for the team.
Token sales were completed a week ago, and the bounty should have ended yesterday but the bounty manager chose to extend it. This is the second extension.
I thought why didn't they make a new round instead of extending? That will make everyone happy. Right?