Not that this actually happened to me, but I think I was either clicking TOO soon for it to realise i was referring to the hazard I was sure was coming up and because I thought it might have counted it, I didn't click again for it, or I clicked on a later hazard that wasn't a hazard, and effectively scored 1 out of 5 for doing it "too late"... I dunno, it's friggin confusing.