Factual error: In several different episodes characters are escaping on foot to Canada, as evidenced by Ontario license plates. But the show is set in New England, and the only way to get to Ontario through the Eastern United States is by crossing a major body of water: The St. Lawrence River, Lake Ontario, The Niagara River, or Lake Erie. You can't walk there.
Continuity mistake: The doctor tells June that she needs stitches. He walks away offscreen and his reflection shows that he immediately kneels down. From a different angle, he is standing, walking several meters ahead, and he doesn't kneel after several seconds later.
Revealing mistake: June goes to an airstrip to fly to Canada, but all the abandoned aircraft on the field are ex Canadian Air Force, meaning it was probably filmed in Canada.
Women's Work - S2-E8
Continuity mistake: Nick picks up the letters that he hid in his trunk, and there are a lot fewer letters than originally shown.
Continuity mistake: In some scenes it's Winter and then the next scene there are leaves on all the trees and flowers in flower pots.
Continuity mistake: When Offred watches her daughter asleep the girl's head is turned to the left, then for a brief shot it swaps to being turned to the right. Then back to the left for the rest of the scene.
Continuity mistake: When she is standing in the closet you see she still has the tag on her ear, even though she cut the top of her ear off in a previous episode. (00:23:08)
Suggested correction: There was a clip showing her having it put back on when she was recaptured before.