There is also the "faster than light neutrinos effect". It the result was true, the authors would get a Nobel price. If it was false, the authors would look like morons. So they decided to publish the FTL-neutrinos result informally, and as asking help, and with a lot of caveats. If it was true, they'd get their Nobel anyway. If false, they were just asking for help debugging a strange unexpected result.

In less interesting problems, the authors may decide to just not publish it.

In political areas, it's a risk that the far-right or far-left decides to support your preprint and later when you find the error claim that Big Something paid you to suppress the true. And the other side to claim that you are a far-other-side supporter.