Since he nevertheless won the game, it is possible that Capablanca did not feel too bad about this incident. Except that I am pretty sure he still felt very bad about it. The reason is that it must have reminded him of one of the worst moments of his life, the draw he made with Alekhine in game 27 of the 1927 World Championship, Capablanca vs Alekhine, 1927. That game was decisive for the result of that match. Capablanca had not been playing well, and he seemed very unsure of himself. In this game of the match he outplays Alekhine completely, and is carrying out a deadly attack against an Alekhine that had not understood the requirements of the position. At move 35, in a completely lost position, Alekhine plays a bad move, but one with swindling possibilities: 35...Qf8. He allows the taking of the g6 Pawn, that spells the immediate end of the game, but he is threatening the c5 Pawn with check. Well, in his book on Capablanca, V. N. Panov writes that, to Alekhine's amazement, Capablanca missed this threat. He played 36.Rgxg6, which is a good move, but then Alekhine played 36...Qxc5+, and he tells us that Capablanca was so rattled that he made a terrible blunder in his move after the next. After 36...Qxc5+ 37.Kf1 Qc1+ 39.Kf2? the game is a draw because of the variation 38.Kf2? Qd2+ and if White tries to find shelter from the Queen checks in h2 he loses after 39.Kg1 Qd8+ 40.Kh2? Qh5+ and it is Black who wins. So in this game of ill-memory for Capablanca, played eight years before Kan's game, he misses in his calculations a check by the Black Queen along the diagonal g1-a7, and also plays Kf2, which is a bad blunder, just as in Kan's game. Instead of inflicting a crushing defeat on the challenger, Capablanca verified Alekhine's claim that Capablance was not so exact. We all know what happened next.