Amazon published reviews for a novel by the Scientology founder on the page for a new book on Donald Trump, according to tech news site Gizmodo.
"I was scared to be the biggest piece of garbage I've ever read," a reviewer from L Ron Hubbard's Fear wrote in 2000.
These and other reviews of the novel were briefly associated with anxiety: Trump in the White House, by Bob Woodward.
The BBC has asked Amazon for a comment.
L. Ron Hubbard published 1940 Fear, a horror thriller.
It follows James Lowry, a university professor who believes that he is haunted by supernatural beings or demons.
As Goodreads notes, "Lowry is pursued by a dark, secret evil that turns his whole world against him while whispering a warning out of the shadows."
"We are in Crazytown"
Woodward's Exposé at Trump White House is currently a bestseller selling 750,000 copies on the first day.
It contains a series of quotes from White House staff criticizing President Trump's dealings with the presidency.
"We are in Craztown, I do not even know why each one of us is here, that's the worst job I've ever had," Chief of Staff John Kelly said.
The review mix seems to have been resolved now.