I haven't identified an outright fake one but in my experience (mainly in sensor development) most papers are at the very least optimistic or are glossing over some major limitations in the approach. They should be treated as a source of ideas to try instead of counted on.

I've also seen the resistance that results from trying to investigate or even correct an issue in a key result of a paper. Even before it's published the barrier can be quite high (and I must admit that since it's not my primary focus and my name was not on it, I did not push as hard as I could have on it)