We've devised a system to where we give the popular icons an individual 3-digit code and then just do data entry rather than scroll through some 400 icons to select one each day to populate our weather graphics.
Apparently, I had a typo in the code for the full sunshine icon -- the golden orb that has zero clouds on it; one we save for the sunniest of sunny days.
Over six months passed, and the typo went unnoticed, because the full sunshine icon never got used! Then today, July 3, we finally trotted out the icon... only to find it didn't work for the creation of our online version of the 7 day forecast. (Our on-air broadcasts were unaffected as they use animating flipbooks instead of a static photo and... no typo there.)
It's fixed now, but a smirk that it that long to find it -- only in Seattle!
(P.S. As an aside, that image isn't used on our site any more as we've gone to the skyline forecast graphic you see on our main weather page, but we still provide the graphic for other sites who want to use it.)