Bounty hunters always dump always because most of them don't really believe in the future of the project.
They are after the stakes they will receive after the bounty, and immediately they receive it, the next thing that comes to their mind is how to turn it to cash, they don't really care about the price, they just want to dump it to receive peanuts.
Moreover they are scared maybe the price will fall, because they don't believe in the future of the project.