Opening lead K♥; Table result EW-100
Both defenders at this local club were strong players, but still were unable to play in perfect tempo at a critical time in the above deal, and East, who looks and behaves like SB, was quick to pounce. South led the king of hearts against the pushy game, and declarer ducked, North playing the jack, won the next heart and ruffed a heart high before drawing trumps in two rounds, on which South discarded the seven of diamonds. Declarer led the nine of diamonds, and, after a moment's thought, South went in with the ace, worried that East might have Kx Kxxxx in the minors, when playing low would be fatal. North played the three of diamonds, also after a moment's thought, worried that the jack of diamonds might cost or say "don't play a club". South cashed the ace of clubs and continued with another club when North encouraged with the eight and declarer was one off. "Do you agree there was a BIT by both North and South on the first round of diamonds?" asked SB. Both agreed there had been a slight tempo variation. "Director", bellowed SB. When he arrived SB continued. "When North played the three of diamonds with a slight BIT on the first round of the suit, South had UI. NS were playing standard count, and therefore South should have played his partner for Jxx in the suit, in which case it would cost him nothing to exit with a diamond. When North broke tempo, ever so slightly it must be admitted, South guessed that he had J3 and did not want to play the jack. With JT3, North would have played the 3 more quickly. It was an LA for South to exit with a diamond, playing me for AKQx xx Kx Kxxxx, when the contract would have made."
How do you rule?