Continuity mistake: Near the beginning of the film, Kate finds a bas relief that has been partially destroyed and replaced with unadorned stone. As it turns out, she destroyed it herself in the past. However, when she does so, she eradicates almost the entire framed portion. In the present day, only the lower part had been dismantled.
Continuity mistake: In the scene just before the group is sent back to 1357, as they are standing in position inside the time machine, Doniger calls up to Stern, who is waiting at the top of the stairs, "Josh, come down!" However, exactly before this, Josh Stern can already be seen descending the stairs to join the others, although when Doniger calls up to him, he appears at the top of the stairs again.