During the "Minstrel Show" number, the words go: "Oh, Mister Bones! That's terrible!... Ah, ha!... Yes, Mister Bones, that's terrible!... Oh, ho!" Watch Danny Kaye. He flubs the lip-sync and mixes up the "Oh, ho!" and the "Ah, ha!" Apparently, Bing Crosby and Rosemary Clooney noticed because, for a few seconds, it looks like they're trying not to laugh. But the pre-recorded soundtrack covers up any giggles that might have been happening.
At the Inn when Judy is trying to convince Phil they should pretend to be engaged she has him cornered on the couch and we hear him say the words 'I feel the same way about my cocker spaniel.' His mouth says something else.
During "The Best Things" dance number, at the end of the number, on the very last twirl around a kneeling Danny Kaye before she falls into his arms, Vera-Ellen trips over Danny Kaye's outstretched left foot. She recovers so smoothly that it is very difficult to catch.
While Phil and Bob are lip-syncing the song "Sisters" (allowing Judy and Betty time to escape out the window), there is a phrase at the end that Bob (Bing Crosby) messes up on. "Lord help the mister who comes between me and my sister; and Lord help the sister who comes between me and my man!" Bing Crosby messes up on the last phrase and says "Lord help the mister" instead of "Lord help the sister". It's very obvious that Danny Kaye catches the mistake.
The General blows out the candles on his cake after the surprise by Wallace & Davis. At the end of the movie during the song "White Christmas" as they pan back to the General's table all of the candles are lit again.
Right before the "Snow!" number on the train, the menu in the background is lying on its side. At the start of the musical number, all four singers simultaneously look at the menu, which has now righted itself with no apparent help from them.
A full orchestra can be seen in the orchestra pit at the beginning of the dress rehearsal for "The Minstrel Show" number. When the number is over, the orchestra has disappeared, even though they were playing just moments before.
When Davis and Novello are talking about the sheriff, Davis suggests that Novello continue keeping the sheriff busy and then pushes Novello through the door and follows him through the door. However, when the camera follows Davis through the door, Novello is nowhere to be seen.
When Wallace and Davis are meeting the General at his Inn for the first time. Phil Davis is wearing a scarf around his neck that changes from across his chest to the right side of his chest and back again.
When the girls come back onstage during the "Back in the Army" song, their pants are at normal ankle length, yet a moment later when the cut-outs are raised in front of them their pants are already rolled up.
When Wallace and Davis leave the dressing room after doing the "sisters" number, they leave the feathers they were holding. However, when the girls sing for the first time at the Inn, they have them again.
The Haynes sisters go to bed in a drawing room, but wake up in berths. (Since two separate trains are shown, this may have been done to suggest a change of trains - however, none is mentioned, and the "A" drawing room door behind which the girls were seen at the start of the trip is directly behind Phil and Judy as they watch Bob help Betty out of her berth.)
The train that transports The Haynes Sisters and Wallace and Davis from Florida to Vermont is shown as being of the Atchison, Topeka and Santa Fe Railway in one sequence, and of the Southern Pacific Railroad in another. Neither railway ran on the east coast of the U.S.
There are several "goofs which aren't" during the "Gee, I Wish I Was Back In The Army" song. Betty and Judy have pants on. When the hometown character set flips up their pant legs are rolled up. Some people consider it a goof that you never see them roll the pant legs up, but Betty and Judy have just been offstage for a few minutes, and come back onstage with their pants rolled up. Bob and Phil are seen to produce hats "out of nowhere" to match their hometown characters - if the hats had been kept anywhere on their persons during the number up to that point, they would have made obvious bulges in their costumes. But again, Betty and Judy just came back onstage, obviously carrying their own hats, and the four characters circle for a few seconds before the cutouts come up. The girls could have passed over the new hats then.
When Bob Wallace remembered he had picked up a letter for Gen, Waverly, he says that the letter was from the War Department. The movie was released in 1954 and the War Department had been changed to the Defense Department in 1947. However, Captain Davis never served in the military under the Defense Department (having been mustered out by 1947), and would naturally call it by the name he knew.
Early in the movie when Bob and Phil go to The Florida Theater, they tell Novello they are there to see The Haynes Sisters. Novello then goes to the girls' dressing room and tells them that Bob and Phil are there to see their act because the girls' brother had sent them a letter, but Bob and Phil hadn't told Novello that.
The enormous chorus of singers and dancers in the musical numbers, not to mention the army of technicians and musicians required to put on the "little show" at the General's inn, are nowhere evident in the story scenes. It would obviously take an immensely larger accommodation than the inn to house them, anyway.
A distinctive red bass drum used in the opening wartime scene at Monte Cassino as Captain Wallace performs White Christmas is conspicuously visible again just outside the dressing room of the Haynes Sisters at Novello's back in the USA several years later.
Early in the film there is a scene from the control room for the Wallace and Davis radio show. An engineer is seen sitting in front of the audio mixing console, but the VU meters that would show the level of the audio being sent out are not moving.
When the General blows out the candles on his cake, the ones on the far side of the cake blow out obviously from another direction, and almost before he blows out the ones nearest him. He wouldn't have had enough air to blow them all out at once from where he stood, due to the size of the cake.
Near the end of the movie, Emma, Judy and Betty dash out of the far side of the entryway, supposedly to get to the backstage, in the opposite direction. By the size of the 'inn' (set) it would have taken them several minutes to get there, yet Emma - within one minute - is calmly standing just inside the barn to welcome the General to his surprise.