Right after the flower shop scene, Alfie rides his scooter to Liz's place. Only the flowers are not in the basket or anywhere on the scooter. Yet as he comes around the corner of the stairs towards the apartment, he has the flowers in his hand.
Outside the cafe after meeting Julie, Alfie's scarf disappears and reappears between shots.
When Nikki is painting Alfie's Apartment, she approaches Alfie holding a cigarette. When she's going to touch Alfie with her painted hands, she has the cigarette in her mouth. Then the angle changes and she has it again in her hands.
When Alfie and Marlon are sitting in a bar and Carol stands at their table, Alfie's sitting position changes.
When Alfie is in Liz's apartment drinking absinthe Liz's kimono alternates being over both shoulders and then off one shoulder. This happens at least 6 times.
During the scene at the florist's shop (supposedly in downtown Manhattan but filmed in Liverpool), there is a shot looking into the shop from outside. A couple of small Regency-style terraced houses, clearly inappropriate for the film's setting, can be seen reflected in the window.
When Alfie is driving from Manhattan to visit Marlon and Lonette, he crosses the Brooklyn Bridge, which goes to Long Island, not upstate New York where they live.