Chewbacca's Confusion in The Force Awakens

In "Star Wars: The Force Awakens" (2015), Han drops his parka on the floor when he arrives at Starkiller Base. When he leaves, Chewbacca hands it back to Han, and he reacts with confusion. Joonas Suotamo, the actor who plays Chewbacca, improvised this scene and confused Harrison Ford by deviating from the script.