"Klaatu barada nikto" is a phrase that originated in the 1951 science fiction film "The Day the Earth Stood Still". The humanoid alien protagonist of the film, Klaatu (Michael Rennie), instructs Helen Benson (Patricia Neal) that if any harm befalls him, she must say the phrase to the robot Gort (Lockard Martin). In response Gort relents from destroying the Earth and resurrects Klaatu from death.
A phrase that was not said to Lockard was "The Day the Earth Stood Still"
"Klaatu barada nikto" was clearly the phrase that was said to Lockard as said in the first sentence, and the title of the film is incorrect as a phrase. The system was unsure on whether it was correct or not and that likely stems from the use of the title as it couldve confused the interpretation.