Of course no doubt that it's all the bounty participants that caused the price dropping of a certain project, well I've been here in the forum for the couple of months and to observe the things... here's what I've found out.

1. Most of the bounty hunters have more than 1 accounts.
2. Once the project hits an exchange they will sell it immediately (They're afraid that their profits will go into waste if they hold the token for too long)

The fact that running a bounty campaign is one of the best thing in order to gain traffic from users of cryptos but one of the most risky way for a project because of the bounty hunters.