All the time, in my case. Today I got the order of parameters to a callback wrong ("error" was the last rather than the first parameter). The documentation did

All the time, in my case. Today I got the order of parameters to a callback wrong ("error" was the last rather than the first parameter). The documentation didn't say anything about parameters, it only said that the callback would be called with a result. I had to look into the source code to discover the details. I am not sure if Flow would be able to catch this kind of bug but if so, it would certainly save me a lot of time.