You can do both as joining bounty campaign and posting a report is not prohibited in the forum, you just need to make sure that you will also post to other threads aside from bounty campaigns and the most important avoid supporting scam projects so your account will not be tag also. Bounties are a big part in the forum and many project owner wants to make you a report in their thread so they can also bump their bounty thread.

At the past there are very few that do that kind of tricks as the submission of report at the past is via google form and etc. but right now the bounty hunter the same with the project team are upgrading their technique in order to gather some supporters because their thread will be on top in the forum if someone will post a report of their work in their bounty thread.