Some people release something as FOSS but don't understand what that means. We had a developer we worked with at PortableApps.com release his software under a FOSS license. He requested we package it portably in our format and release it. His users and ours were happy.
Fast forward 3 years and a bug impacted a user's data in the portable package. The developer became increasingly irate even after it was fixed and demanded we stop publishing it. To avoid confusion, I even renamed the portable package to a new app name, forking it. That made him even more angry and he started publicly claiming we were "stealing" his work, despite following the license, maintaining his copyrights, and directing users to donate to his donation page to support development. He put up banners on his website and documentation pages about the "theft". As his emails to me went downhill, I got the feeling he might poison the code itself upstream to mess with the fork. I didn't want to deal with that just for one small app, so I abandoned it.
So, yes, this does happen. And some people thing "because I said so" is a valid position.