Lost ballot box
I was standing for election to my Borough Council in England. The count began on the morning after polling day.
By about midday we had a result, although the number of votes did seem rather low. Then a very embarrassed official turned up. "Sorry, chaps, we've just found this extra ballot box."
All the officials were red-faced, that they had goofed. We candidates, however, were feeling, "Oh sh*t, we were just about to go home for lunch."
The count resumed after lunch. It did not change the result, but it did make the voting numbers look more respectable.