Well it's simple because a bounty hunter dumps at any giving price without minding the price of the token, when a token is launched on the exchange, people will normally price the lower and some bounty hunters will still at that given price.
Actually not everything is like that. As a bounty hunter, I also want to get the best price. If the project is potential and good, then I will hold back and be patient to get the best price.
Most people seem to forget that bounty-hunters aren't getting their reward for free - they're paying with their time instead of money and obviously aren't interested in selling their rewards ridiculously underpriced. Recently the reason for ICOs being traded below the ICO-price is more likely the current market's fault.