This reminds me a phone screening that I self-sabotaged:

In the "skills" section of my resume I have a list of technologies that I have "limited experience" with, on which I have included C# and Python.

During the interview the interviewer started a question with "In C#..." to which I interrupted him to mention that my knowledge of C# was pretty limited. The question turned out to be a pretty easy question about OO (or something like that). The next question started with "In Python..." and I again interrupted him, only to have him ask an easy question about dynamic vs. static typing.

This is sort of the opposite problem, where I was so afraid of overstating my abilities to the point where I made myself look bad.