According to Snopes, it is FALSE.
Near as I can tell, the initial agency took an old recording and subjected to a "voice stress analyzer". A device currently popular with police in place of full on lie detector equipment. His comments about spotting something, possibly spacecraft debris, on his trip to the moon, were dubbed true and spun to mean UFO. IMO something of a stretch.

Did Buzz Aldrin ‘Reveal the Truth About Aliens’ in a Lie Detector Test?
A British tabloid published an "exclusive" based around an alleged analysis of a statement already refuted by Aldrin.

On 8 April 2018, an English tabloid attempted to pass off a long-debunked conspiracy theory about astronaut Buzz Aldrin and three of his peers as an “exclusive” by involving a questionable research group.

According to the London-based Daily Star, Aldrin — as well as Gordon Cooper, Edgar Mitchell, and Al Worden — “took part” in a study by the Institute of BioAcoustic Biology in the United States. The fact that Cooper and Mitchell are both dead is not mentioned until the story’s penultimate paragraph.

Despite stating in its headline that Aldrin (who piloted the Apollo 11 mission in 1969) passed a “lie detector test,” the Star reported that the four astronauts’ “participation” consisted of an alleged analysis of recordings of the two men’s voices. But there is no mention of which recordings were covered by the “complex computer analyses” of their voice patterns; instead, the Star reported that “these studies are claimed to be more reliable than current lie detector tests and could soon replace those used by the FBI and police,” without stating exactly who is making said claim:
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