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Any pile of debris dense enough would have to be immense and far away from the star so that the phenomenon would remain stable. So your dead star or very large non-stellar companion, being smaller, would have to be orbiting close enough to block that 22% of its light.
A black hole might explain it, but then the visible star would also show a wobble (to say the least) and lensing, and neither is present AFAIK.
Maybe the star has lost luminosity on one side, due to some kind of, uh, encounter, or other phenomenon.
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