Continuity mistake: When Lars approaches Margo in her booth in their office, you can already see some letters in the third line of the last paragraph on her screen. When he is leaving, she continues typing, but there, you see her just beginning the third line. (01:08:00 - 01:09:00)
Continuity mistake: After church when Lars and Mrs. Gruner walk to her car, she opens her trunk and Lars places some flowers in it. Mrs. Gruner then puts her right glove in her left hand and hands over a rose to Lars. She closes the trunk, still holding the glove in her left hand. When it cuts the glove is suddenly in her right hand.