Factual error: The stolen Sienese School painting is painted on canvas. Nobody painted on canvas in the 14th century, wood panels were solely used.
Factual error: When Tom uses Lena's glove to trigger the fingerprint reader he failed to realise it would provide the mirror image of the print. (00:22:59)
Lord Baltimore (No. 104) - S2-E1
Other mistake: When Rowan shoots the suited men with the sniper rifle, the camera angle shows members of the public watching the filming and filming the the production on their phones. (00:28:46)
Abraham Stern (No. 100) - S5-E11
Character mistake: Reddington says that the 1943 pennies he is hunting are special because they were made of bronze when all other pennies were made of copper. The 1943 pennies were actually the steel pennies from WWII as to save copper for the war efforts, there were some copper errors that year, but the majority were zinc and not copper.
The Travel Agency (No. 90) - S5-E6
Factual error: The scene in 1989 has a VHS/DVD recorder in the left bottom corner. (00:01:00)
Answer: The man Red killed, Sam Scott, was Lizzie's adoptive father, not her biological one. However, at that time Lizzie (and thus the audience), was led to believe her real father abandoned her and her mother, so expect more secrets to be revealed how her real father actually died (or if he's even actually dead).
Bishop73