Factual error: When Fleming salutes Cholmondeley and Montague, they return the compliment whilst not wearing their headdress. Members of the British armed forces never salute if they are not wearing a hat, instead they would stand to attention.
Continuity mistake: On the rooftop while shooting at the Russians, John dives through a skylight. In a side shot he's falling back first, then he lands on his front.
Character mistake: Immediately after kissing (through masks) and having close contact with JJ, Valeria removed her protective mask and went to check on her sick/crying child. Valeria was clicking her tongue, kissing her child on the face/head and putting her hands around the child's ears/hair. Valeria did not take appropriate preventive measures for contracting and/or spreading COVID-19. (00:18:40 - 00:19:29)
Factual error: At the end of the film, Hellfire Jack returns the toy soldier to the son of the late William Hawkins in 1917. Hawkins son is shown taking it upstairs and placing it in front of a photo of his father, in between two medals. These are the British War and Victory Medals - these did not exist until 1919, and in most cases were not even issued until the 1920's.