In one scene General Silva is having a conversation with Eleazar ben Yair. One of the men's chain around is neck is stuck around a pin on his body armor in one camera view, but not in a different view.
When the zealots try to hide the body of the legionnaire they have killed by the goat pen, the dead man lifts his head before they lift him up.
During the scene in which the Jews are ascending the trail up to the summit of Masada, a vehicle the size of a bus can clearly be seen travelling on a road in the background
When Eleazar and his party descend down the mountain during their nighttime mission, notice their feet. All of them appear to be wearing 20th century sneakers.
At approximately 23 minutes in, we get a close-up of an obvious modern fiberglass bow covered in what appears to be black electrical tape.