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.
you are right. if you support a project through a bounty, then you need great confidence from the project. I think research is the most appropriate thing to do. to make yourself truly convinced by a bounty, then you need to research it to the bottom of the project concept.