Not 50, but for example every photoshoots 3-4-5 times until you got enough submission points to get full scene.There is no event in AFV you need to do 50 times to see a new scene. In fact, I can't think of any event other than delivering from the warehouse that you need to repeat without seeing something new.
If you're doing a event and arn't seeing anything new, then repeating it over and over isn't going to unlock anything. Try checking your phone and completing other events. Sidney's night scenes are a good example of an event that's progress is paused until you've completed other events.