An ex of mine edited a wiki article and added false information to it. I think that sort of thing is very harmful, so I removed it. A day later the edit was reverted. I tried a few months later. It, too, was reverted.

I had someone else try. It was reverted. I tried once more, probably two years later (after the "fact" had time to propagate throughout the internet), and it too was reverted.

The reason it was reverted every time? Apparently I didn't sufficiently explain the edit. It didn't require explanation: it was an uncited, demonstrably false fact. It asserted the existence and publication of a book (in recent history) that was never published. It is impossible to find a copy of it. It does not exist. I didn't know how to explain it any better than that.

A few months ago, I saw that someone finally noticed it was fake and removed it for good.