It kind of is. During this scene harry is under the effect of a "liquid luck" potion he won in potions class. In the book he does act a bit goofy. For example, he takes the potion because he needs a bit of luck to persuade a professor of something, but the moment he takes it says something like "well, I'm going to hagrids." Ron and hermione are like "wtf mate, ur supposed to go persuade professor slughorn" and he's like "nah, I've got a good feeling about hagrid bro."

So ya, moral of a the story is yes, he is supposed to be acting a bit goofy at this time.