In the wedding scene, the groom's ribbon rack is placed upside down. It looked like the ribbons were in the correct order though.
A reserve unit would never schedule training two years in a row on Christmas. Reserves take their holidays seriously.
In the wedding scene, the best man is wearing a beret. The groom should also be wearing a beret.
Main character does not follow Army grooming standards with his out of regulation haircut. AR 670-1
Main character's military ribbons on wrong at end.
Groom wears a fourragère in the movie that has not been issued since World War II.
Some of the scenes in military uniform show the main character without any patches. There would never be a situation to wear uniform without name tapes and rank.
The tactical vehicles have GSA license plates in the movie. Tactical vehicles in real life have painted bumpers.
The COL with possibly over 20 years of military experience wears a civilian coat unzipped. The Army has cold weather gear and Soldiers will keep all uniforms button, zipped, or snapped according to regulation AR 670-1.