It looked like a petulant blunder by the challenger, who had become more fussy and prone to complain about the conditions under which he was forced to play chess which each passing year. He had repeatedly accused the Russians of cheating, and lying. Now he had thrown a match.
In retrospect, it looks much more like a clever ploy in a psychological war against Spassky and the Soviet apparatus. From then on, Spassky never knew what Fischer would do next, but he hung on gamely as the American repeatedly beat him.