I had a rejected journal submission show up again as a keynote conference presentation a couple of years later. To be fair, with that sort of thing we could have just had the exact same ideas and so forth, but it wasn't a common research topic, and there were suggestive dots easy enough to connect. Regardless, it raised all sorts of alarms about what might have actually happened, and I started thinking seriously about the value of non-peer-reviewed, completely open publishing just as a way of maintaining authorship credit. Even if everything were totally innocent, it was a bit unnerving about the attribution of ideas and everything.
I'm having major conflicts about academics as a career. It seems to get more and more insane every day.