Because most of this year's ICO projects have failed, bounty hunters are quick to sell when COINS go on sale. Because they want to reinvest them in other COINS, some sell because they're afraid the price will go down.
some ico coins cannot survive the current market. after selling the ico and being listed on the trading market shortly after that the price will immediately drop. that's what made the bounty hunter immediately set up. even with bounty hunters participating in selling the tokens they get it also makes the decline worse. because I think it's not just a bounty hunter who sells tokens that are obtained but some investors also do the same thing. therefore many projects are now locking tokens to bounty in a few months to maintain the value of tokens on the market.