The story of how some of Bernard Kettlewell's famous peppered moth experiments contained certain flaws.
All very interesting stuff, and it did bring out the humanity behind the textbook science, but I couldn't help feeling that some of Kettlewell's failings were over-exaggerated. The phrase hatchet-job occasionally sprang to mind.
Postscript: Kettlewell's original flawed experiments have now been repeated with the flaws removed. His original findings were confirmed.