The tendency to notice mistakes shortly after a resource is made public. Characterized by a direct correlation between the impact of the mistake and the size of the audience. Variant of Murphy's Law.
"Oh no! I didn't catch that typo until after I hit the 'Publish' button! Harding's Law, huh?"
"Why is it so reliable that I see an error in a file 30 seconds after I send it out? Must be Harding's Law at work."