Factual error: The Royal Navy sailors are shown with just 'HMS' on their cap tallies. This was only seen in the Second World War for security reasons. In peacetime, the tally bears the name of the ship or shore establishment to which the rating is assigned.
Deux Amours - S1-E5
Continuity mistake: Daryl fights the walker on the ship after it kills the other prisoner. He gets backed into a corner and jumps off the boat just as the explosions are happening. The walker he was fighting disappears.
Factual error: Season 1, Episode 10: Lee is trying to get out of the underworld on his capsule with the rescued others. They all get in, and he closes the top hatch by turning the hatch wheel clockwise. Trying to take off, a wire becomes disconnected outside, and Lee has to go out again. He turns the hatch wheel clockwise, and this time it opens instead of closing. If it was clockwise for close, it should be counterclockwise to open.
Factual error: There are two Marines posted at Marine 1, the Presidential helicopter. Their pants are ridiculously long and not the image of Marines with well-fitted uniforms. Their position of attention is wrong, with the hands clenched and placed on their thighs as opposed to being fixed at the sides. Worse, when they saluted with their right hands were above the service cap brim, instead of the fingertips touching the bottom of the brim.
Continuity mistake: When talking on the roof at the start, the guy in green has his hands in his apron pockets when being told the security cameras are off. Cut to a wider shot and his arms are folded instead.
Character mistake: Issei meets with a journalist to tell her that he has decided to end his participation in the contest to win the estate. She hands him her business card, which he immediately puts in his pocket. This completely violates the Japanese traditional business card ritual, which includes looking carefully at the card (a sign of respect).
Continuity mistake: As Jizzlord says, "so really, this is a good thing", he's holding the posters upright, facing Jen. Cut to a shot from the side and he's holding them horizontally, facing upwards.
Factual error: Karl Silberbauer, who headed the raid on the secret annexe, wears the insignia of an SS-Sturmbannführer (major). He was actually an SS-Hauptscharführer (senior sergeant). His superior is addressed in German as "Herr Major" (not an SS rank and not how an SS officer would be addressed), but wears the insignia of an SS-Standartenführer (colonel).