Both in the courtroom and in General Worden's office you see a modern American flag with 50 stars, even though that flag first came into production in 1960, with Alaska becoming an American state in 1959 and Hawaii following the year after.
As the Dirty Dozen fly into France in a disguised C-47, one team member asks why they did not parachute in. Major Reisman replies that they have no parachute training and would likely die trying to parachute in. 20 minutes later, after the team tries to mutiny in the French church, there is a scene in which the entire team parachutes into France.
When Sixkiller is running and shooting with the MG42, the weapon jams, but the sound of bullets being fired continues.
The amount of ammunition Sixkiller has for the MG42 also varies from shot to shot.
In the parachute jump, the riser lines were loose and too spread out in the close-up shots compared to the distance shots that showed the lines tight and closer together since the far-away shots were actual paratroopers coming down.
Dregors the sniper, armed with a scoped rifle, and Major Reisman confer as to the range of the sniper's shot and agree that it is around 70 yards. Not only is a 70 yard kill well within the range of any basic infantryman with a standard rifle using iron sights, 70 yards is within the range of a competent US army pistol marksman. No need for Dregors and his sniper skill.