In numerous outdoor scenes in the movie, the sky in the background changes from clear to partly cloudy to overcast to rain clouds between shots, indicating that the scenes were filmed over several days with different weather each day.
Tattoo on the stomach of Luther Billis disappears and reappears when he is stranded in the lifeboat.
While singing "I'm Gonna Wash That Man Right Outta My Hair", the soap on Nellie Forbush's shoulders disappears and come back.
In the first scene between Nellie and Luther Billis (during the song "There is Nothing Like a Dame"), Luther's shirt unbuttons and rebuttons itself several times.
The appearance of African Americans as Seabees is not an error. Over 12,000 such sailors served in the Construction Brigades, despite segregation in other parts of the WWII military.
In the beginning of the film, the controls of the pilot and co-pilot are not really linked. It's obvious that the pilot is turning the wheel but the co-pilots is not in sync. It's turned by an unseen hand.
Although the cockpit of the seaplane appears to have all its glass shot out, the crew never show any effect from the wind that would be whipping through.
When Luther Billis is paddling away from the gunfire, the cable pulling his lifeboat can clearly be seen.
Towards the finale of "Nothing Like a Dame", Nellie jogs along and picks up her party dress from Luther although she won't even be invited to the party until several scenes later when she meets Emil.
Lt. Joe Cable flies in on his mission in a PBY Catalina at the start of the film but when he walks off the short pier to the beach at his destination there is no flying boat in the lagoon behind him, Had he really just disembarked from a plane, it would still be present.
When Luther Billis is in the lifeboat being fired upon by Japanese troops, the rear of the lifeboat shows its manufacturing date as 'APR 1956'.
At least one of the Jeeps shown is a model M-38 from the 1950s.
In the initial Bali Hai sequence, the native girls are all dressed like they're heading for the 1958 prom, in typical 1950s mid-calf flared skirts, despite the fact that the story is taking place in the 1940s era of World War II.
All of Mitzi Gaynor's hair styles, as well as the style and cut of her uniforms, when worn, and, especially the party dress in the last sequence before the mid-way intermission, are strictly 1958 and nothing like what was being worn during the time of the story, i.e. the mid-1940s.
When Nellie asks Captain Brackett if the "Frenchman" on the island she's heard about from all the pilots in the hospital is "her Frenchman," there's a complete mismatch between what she says and the movement of her lips.
During "A Wonderful Guy," there's a part when Mitzi Gaynor's lips aren't synchronized with the music whatsoever.
Liat's lips are not even slightly in sync with the song's words when she sings "Happy Talk."
Liat does not understand English. But when her mother sings "Happy Talk," in English, she shows by her gestures that she understands what her mother is singing.
It doesn't make sense for Bloody Mary to encourage the young couple to engage in happy talk about many things, when the only language they share is a few words of French.
Emile is supposed to be a Frenchman, but speaks English, and sings (dubbed) with a heavy Italian accent.