In the song "What You Own" when Mark is riding in the passenger's seat of the Buzzline van, a banner promoting the New York Olympic Bid for the 2012 Olympics can be clearly seen on a light pole. These banners didn't go up until 2004.
The film takes place between December 24, 1989 to December 24, 1990. Yet, many modern automobiles built well after 1990 are present in the film. An example are the Ford Crown Victoria NYC Taxis present in the film. Ford Crown Victoria was not introduced until 1992, nor were the current generation of these taxis present in the film introduced until 1998.
On the subway with Collins, Roger, Angel, and Mark, we see Collins hold out a cup while he sings "Santa Fe". After returning Roger's coin, we see Collins throw the cup onto the empty seat behind him (screen left). In the next scene, we see the cup next to Angel, in a completely different seat.
During "Out Tonight", as Mimi is opening her windows, about to step onto her balcony, her sleeves are not rolled up. When she steps out in the next shot, both sleeves are rolled up to her elbows without her having time to roll them up.
Throughout the movie, Mark and Roger's answering machines repeatedly switches between answering after one ring and answering after two rings. A person could argue that the number of rings was changed by either Mark or Roger, but at the beginning of the movie, on Christmas day, it rings a different number of times for Maureen's call than it does for the call from Mark's parents, and no one has made any changes to the machine.
Before "La Vie Boheme", when the characters meet up outside, Maureen and Angel go to hug, yet when the shot is taken back from afar, Mimi appears to hug Maureen and Angel stands there with arms crossed.
During "La Vie Boheme" when everyone sings "To S&M" Mimi is lying down on the table. In the next shot she's standing up and pointing at Benny as he storms off. In the next shot she's lying down on the table again.
As Roger and Mimi leave the restaurant, after "La Vie Boheme", Roger is wearing a necklace on the outside of his shirt. When he gets outside to sing "I Should Tell You", the necklace is gone. As the couple re-enters the café, the necklace is visible again.
During the "La Vie Boheme" reprise, you can see that the word
AIDS that Tom Collins wrote on the board before Mimi and Roger go outside for "I Should Tell You" is different. The 's' is really sloppy and large when he first writes it, but if you look at the board behind the characters when they are on the bar, it changes size and handwriting.
In "Today 4 U", when Collins clears the table for Angel to jump onto, you see him clearing a blue mug and a brown one, yet when the next camera shot is closer, we see him individually clearing them away.
Benny throws a ball of paper to Roger who places it on the Range Rover . As he starts singing the song "You'll See Boys". The paper continues to move around on the hood of the Range Rover during the song.
Benny throws a ball of paper to Roger who places it on the Range Rover . As he starts singing the song "you'll see boys". The paper continues to move around on the hood of the Range Rover during the whole song
On the subway train during 'Santa Fe,' the woman at the end of the train with them sits down twice - when Collins sings the line 'Computer Age Philosophy' and when the camera goes back to the shot of all four of the people in the song.
During the song 'La Vie Boheme', right before Mimi and Angel sing their "To handcrafted beers..." line, Mimi is seen beginning to climb onto the table. In the next shot she's sitting in her seat, and climbs onto the table again.
During the "Today 4 U" scene Roger is keeping a beat for Angel on his curled leg when the shot is in front of him, his hand that is closest to Collins and Mark is below his knee, but, when the shot is behind him his hands are folded over the top of his knee, and he's not tapping out the beat.
When Mimi is standing in the stair way before the "Candle" song you see Roger go by and you can clearly hear him shut and lock the door upstairs behind him, but in the next shot of Roger he is just shutting the door.
In the beginning of La Vie Boheme when Mark sings "Dearly beloved, we gather here to say our goodbyes", Maureen is seen with both her hands under her chin, but when the shot changes, both arms are down in front of her on the table.
During the "La Vie Boheme A" sequence, Maureen switches places. At the beginning of the "Bisexuals, Trisexuals..." section, Maureen is shown to be in front of Angel, Mark, and Mimi, who are in the middle of the table, in one shot on the line "Bisexuals", but in the very next shot ("Trisexuals"), she is shown to be at the end of the table where she normally is.
In the deleted scene of the final half of "Goodbye, Love", the car parked in front of the entrance leading to Roger and Mark's apartment suddenly changes to Roger's as Roger leaves the apartment to drive to New Mexico.
In the stage musical, the entire first act takes place on Christmas Eve, concluding with "La Vie Boheme." The film spreads the first act over Christmas Eve and Christmas Day, which is reflected in a few lyrical changes in Collins' intro for "Today 4 U" and "Out Tonight" which creates plot holes in the time line. Angel meets Collins the night of Christmas Eve and takes him home after the mugging, but in "Today 4 U" the next day, she sings that she met the lady in the limousine that morning, caused Evita's fall, trimmed the lady's tree, and THEN met Collins.