I Can Haz Chips?

There seemed to be a bit of confusion on table 19.

Two players had checked all the way down a queen-high board with the first player announcing he had {10-?}

for ten-high.

He then mucked his cards, thinking he was beat as the second player began to reveal his hand. However the second player showed down {9-?}

.

As the first player had mucked, the second player was the only one entitled to the pot!

WTF, mate?