Inexplicable

A Q 7 4 2
A K 10 6 3
J 2
6
K 8 J 6 3
9 7 2 J 8 5
K 10 9 7 6 3
A K Q 10 4 2 J 9 7
10 9 5
Q 4
A Q 8 5 4 Contract: 4 spades
8 5 3 Opening lead: K of clubs

Plus 5? For a 100 matchpoints? How can that be? Don't you always have to lose a club, a diamond and a spade? West continued clubs at trick two, ruffed by declarer, who now came to the Q of hearts. I confess that the first time I looked at the hand, I thought it was a diamond finesse that West failed to take his K on, and that was before I even knew what sort of malfeasance had been committed.
But no, that was a lead to the Q of hearts, and the malfeasance occurred at the very next trick: 10 of spades, pushed through, holding. Holding? That's what the record shows and that's why declarer wound up plus 5 with an unchallenged top board. Whether East thought she'd get her J on a later finesse or simply wasn't watching, I cannot say. (I had a partner once, holding Q J low in diamonds after the ace had been played and declarer led to the K 10 in dummy. Declarer went low and so did my partner. "Oh, I'm sorry," said he. "I thought she was going to play the K." Oh? Is that how we play bridge? We decide what declarer's going to do and play accordingly? Not too swift.)
Of course, the above declarer continued the suit, picking up the K, second round, and the J, third round. Nice score.