During the initial flashback to Edward's Yale days, the 'Buttercup' scene fades in on a pair of chain-tuned timpani with plastic heads. In that year, plastic drum heads were not invented yet. They should more accurately have been calf skin. Plastic heads came into use in the 1950's.
When Wilson copies the membership list of the American German Cultural Commitee, the list he copies contains a font that was only recently available on typewriters. None of the "photocopies" in the movie contain features of the mimeographs that would've produced those copies in the 40s, 50s and 60s. Likewise, the photos used to blackmail Wilson later in the film also appear to have been printed on an ink-jet or laser printer.
When an audio analysis is being made of a tape recording, we see the technician using what appears to be a Urei 565 Filter Set. This product was introduced to the market in 1970 yet the scene is supposed to be set in 1961. The predecessor to the Urei 565, the Universal Audio 550-A, would have been available in 1961 but it has a much different appearance than the 565.
When Edward receives his orders from General Sullivan, the NCO who delivers the envelope wears, on his left shoulder, a red/white patch with a capital A for the First Army. That insignia was not approved until March 1949, the First Army patch in use in 1940 was just a capital A on an olive drab background.
During their rendezvous in the early 1960s, Wilson and Laura are shown emerging from the "Old Dominion Tavern," implying they are in Northern Virginia. At the time, Virginia liquor laws specifically banned the use of the word "tavern" in the name of any alcohol-selling establishment.
When the Valentin Mironov #1/Yuri Modin character first contacts Wilson's office in 1953 (film insert), one of the agents claims "man is senior officer KGB...", but the KGB was founded in March 1954 (former MVD, MGB, GPU).
When Wilson enters the tailor's shop in London 1941 during the blitz there is a sign above the counter regarding clothing rationing coupons which was not introduced until June 1941. However it is cold outside and his son is not born yet so the date of the scene has to predate June.
While a Soviet spy is being interrogated, he makes reference to America's "military-industrial complex." The scene is set in January 1960. The term "military-industrial complex" was not used until outgoing President Dwight D. Eisenhower included it in a televised speech on January 17, 1961.
It is about sunset-time when 6 year-old Edward runs into his parent's room and hides in the closet. They must have talked hours, since when Edward is leaving the room, it is the dead of the night outside.
When Edward has returned home from Europe and his son asks about his war service. While Edward is unpacking, at first he is taking out shoes and holding them when he notices his son has come in. Then as his son thanks him for the ship, he is taking out some clothes and holding them as he says "You're welcome." When his son says "good night" and exits, Edward is holding the shoes again.
When Wilson is transferred to Berlin, the first original footage of the ruins of the city is subtitled "Soviet Sector, Berlin". In fact, the footage shows the area around the Kaiser Wilhelm Memorial Church, which was in the American Sector, and later on the center of West Berlin.
When Edward is in Mironov's office, there's a picture of Mironov's family with two daughters. However, this contradicts his legend which states that he has 2 sons (and probably the true Mironov did). It is highly doubtful that he would do such a mistake and nobody would notice that inconsistency.
The scenes in war-time London show the characters walking outside at night under working street-lights, but London's streetlights were not turned on during war-time, in order to make it more difficult for German bombers to locate their targets.
Edward and Laura watch a newsreel filmed in Poland under German occupation; Several days later - enough time had elapsed for Edward to assist the FBI in exposing the members of "The American German Cultural Committee" - the couple go dancing and there they hear the announcement of Britain and France's war declaration on Germany. In reality, that event occurred on Sep. 3rd, 1939, merely 2 days after the invasion of Poland; Bear in mind that in WW-II era it took days for a newsreel to travel from the front to the cinemas.
When Edward is relating his closely guard secret about when he was a child hiding in his fathers closet he says "there was his admirals jacket.", when actually it was a Captains jacket that was in the closet.
The Finnish passport and driver's license include some questionable linguistic choices, which are here literally translated. The driver's license reads KANSAINVÄLINEN AJAMINEN PÄÄSTÄÄ ("international driving to allow"). It is from YHDISTETTY KANSA ("a people unified"), apparently a reference to Yhdistyneet Kansakunnat (Finnish for the United Nations). The license also reads: EI HYVIN PERUSTELTU KOTONA SUOMI ("not well justified at home Finland"). Also the first name is spelled wrong: it reads "Marti" which is not a Finnish name. Most likely it should read "Martti", a very common first name at the time. The passport includes the puzzling statement ESITYSTAITO LLA KANNATTAA ("presentation skill with is profitable").
After about half an hour of the movie when Edward is spying on
Dr. Fredericks at the gathering of the American German Cultural Committee, he searches through a handbag and digs up a membership roster. The title of the list is written both in English and German, but the German translation is atrocious, as if it had been done by translation software. It reads, "The [sic!] Amerikaner German [sic!] die Kulturelle Einrichtung Das Gremium". A reasonable translation, most likely used without article, would simply be "Amerikanisch-deutsches Kulturkomitee". It is highly unlikely that such an institution in which American scholars, not to mention Germans, played a role would fail to use a correct German translation.
The goof items below may give away important plot points.
When Edward reveals Valentin to be a spy working for the Russians, there is a copy of Churchill, Taken From the Diaries of Lord Moran: The Struggle for Survival on the shelf alongside James Joyce's Ulysses. While the scene is set in 1961, Lord Moran's book, which covers the life of Winston Churchill from 1940 to 1965, was not published by Houghton Mifflin until 1966.
In the flashback scene where he is remembering his father's suicide, Edward says that his father's Admiral's coat was in the closet, but the coat he has is clearly a Captain's coat - complete with 4 stripes on each cuff and an eagle on the epaulet.
Near the end of the film, there are two different scenes showing Agent Wilson reading his father's suicide note. The first scene shows him taking the note from his safe and reading it for the first time. Other brief scenes follow it. Then, the second scene shows him reading it one last time before he burns it. But, if you look at the notes, you'll notice that the note used in the first scene is a different note than the note used in the second scene. The first sentence in note #1 starts closer to the top of the paper and includes four words in the first line. The first sentence in note #2 starts further down from the top of the paper and includes five words in the first line. Also, the first paragraph in note #1 is completed in seven lines while the first paragraph in note #2 is completed in six lines.