Originally before the end credits, in the theatrical cut, the alien Wak “broke the fourth wall” and remarked on people who were still in the theater from the smell of popcorn. In the re-edited home video version, he just tells another joke before it cuts to the closing credits.
FWIW, I just checked the Netflix UK version and it does indeed have the popcorn line at the end 😃 Still haven’t got round to checking the 1080p file I downloaded recently, but will try to soon.