I have seen the extended cut and it is right and all! There are no additional joker scenes in the extended cut at all! If you were looking forward to that abandon all hope because this ain’t happeing. DC subreddit got a video that alleges several scenes that were cut from the final version of the film are still missing in the extended cut.
I’m not sure what the reasoning of cutting down joker scenes from the movie, If you have noticed there isn’t much joker presence in the movie. but not all is lost maybe they will hear the cries and include them in some other directors cut or something. Check out the video below for more.