Most of bounty hunters are selling their rewarded tokens after the tokens were traded on exchanges. Also some early ICO participants (with high bonuses) are also selling their tokens immediately. This are some problems why most of the token prices drops after the ICO.
You say that bounty hunters sell their tokens at cheap prices when finished ICO and drop prices on the market, does that make sense? so the allocation for the bounty hunters is very small. I'm not sure they can drop prices on the market.
Most of the time the coin that gained from bounty campaign done a great part on the price, yes the allocation from bounty campaign is too small it is about 2 to 5 percent of the total fund, but when the participants dump it, it will affect the price and also those investors ofcourse they will sell also their coin with their bonuses.