Continuity mistake: At the beginning of this film, Paddington is shown living with two adult bears. The Explorer gives them their names, and introduces them to marmalade sandwiches. In Paddington 2, the bears are shown on a bridge, eating marmalade sandwiches and referring to each other by name before they see the little bear on the log, who is young Paddington.
Continuity mistake: Paddington gives chase on 'dog back' to the thief after he has stolen the book from the antiques shop, catches up with him, but the thief drops a smoke bomb and disappears. The dog is in shot as Paddington talks to the thief, but when the smoke bomb is dropped we get an aerial shot of the whole area and there's no sign of the dog.