Howard's fly mysteriously unfastens and then refastens itself during the "Exploring your Masculinity" dance scene.
When Peter Malloy walks in on Howard Brackett at the cafe, Howard flips his spoon off the end of the table. In the next shot Howard is holding a fork, then in the next shot he does not have any implement in his hand.
During the bar scene, when Emily tells Peter Maloy that Howard didn't like her, he takes her hand with both of his hands and in the next shot, his left hand is away from her.
After Howard is handed the laser disk for "Funny Girl" during his bachelor party, the tobacco wrapper on his cigar has started to unravel. Seconds later, it is good as new.
The hanging strap on Joan Cusak's wedding gown can be seen hanging out of the bottom of her right sleeve in some, but not all, shots at the church.
The timing referred to in the film is way off. The celebration dinner before the wedding is held in the daytime before the Oscars. At the dinner, Howard states that he is getting married on Sunday, in three days. The Oscars are never held on Thursday, they have been held either Sunday or Monday. Meanwhile, this is a short time before high school graduation, which is in late May or early June. The Oscars are now being held in January or February.
The Oscars ceremony among other fictitious elements has one basic error: the poster says it is the 68th ceremony, while the graduation banner and the pupils' hats say it is the year 1997, when the 69th Oscars ceremony took place.
The wedding is to take place on Sunday morning at 9:00 a.m. in a Methodist church. Methodist churches usually have worship services during Sunday mornings and do not schedule weddings during that time period.
In the Confession scene, Howard Brackett tells the priest that his friend has not had sex with his fiancee, even though they have been engaged for 3 years. The priest says, "Then he must go to her. He must be, you know, be with her." Meaning having sex. In real life, a priest would never tell anyone to have premarital sex.
When the guys in the locker room are showering Mr. Brackett with champagne and soft drinks, one of the bottles still has the lid on it, but the guy holding it keeps shaking it anyway.
The outdoor scene where Howard crashes his bicycle.
Outside the diner with Howard and Peter.
In the teachers' lounge.
The outdoor engagement party.
Howard identifies "Color Me Barbra" as Barbra Streisand's eighth album. "Color Me Barbra" is her seventh; "Je m'appelle Barbra" is her eighth.
In the film clip at the fictitious Academy Awards, the Military Lawyer (Dan Hedaya) refers to the "Congressional Medal of Honor". This is a common mistake: it's the "Medal of Honor".
During wedding preparations in the first few minutes of the movie, Stan pronounces nuptials as if it were spelled nuptuals (with a "shoo" sound). It should have an unstressed "shuh" (as in "specials") or "chuh" sound.