In the scene where Nicola and Matteo meet again in Nicola's office after Giorgia has been found, they lay their right hand on each others shoulder. Nicola's hand is transferred from Matteo's one shoulder to the other in the close-up.
(at around 27 mins) After a caption has shown that the film is set in 1966 at the beginning and the main characters are getting into a car, a radio is heard playing the song "Might just take your life" by Deep Purple. This song was released in 1974.
At around 1 hr 21 mins where Giulia is playing the piano during the Florence flood clean-up and meets Nicola for the first time, there is a large string instrument inside a carry-bag which has 'Mokke's Backline Rent Europe' written on it. This scene is from 1966, but Mokke's were founded in 1984.
The song "A chi", played at minute 50.00 when Matteo and Giorgia choose it on the juke-box, was released in 1967 and not before 1966.
In the scene where Mirella is driving the boat out of Sicily, the bottom of another white boat can be seen when the camera focuses on Andrea.
Midnight sun does not take place in November (1966 - beginning of the film) nor during spring (2003 - end of the film), but is visible at the Arctic Circle only from June 12 until July 1.