Always trust your intuition when joining bounty. If you feel something doubtful about the campaign, then maybe there is something wrong about it. You must do some research before joining a bounty campaign so that you will not waste your effort doing bounty tasks.
intuition also doesn't always work, I've joined a lot of bounties but also lots of vain and disappointing,
but I learned because of that, following a good bounty is because of a good bounty manager