Complex sentence: Robert Winzeler came into contact with some Malayans who had known of someone who had latah or them themselves had had latah, and they said that latah was a problem, but it was a problem that could not be resolved.
Split into simpler sentences: Robert Winzeler came into contact with some Malayans who had known of someone who had latah or them themselves had had latah. They said that latah was a problem, but it was a problem that could not be resolved.