When she first arrived, Beverly was a little bit forgetful and left one of her quest items behind. This should be fixed as of September 2021!
You should be able to find the second acetate Beverly asks for in Old-Central District on top of the apartment building to the far left of the island. You'll need the Bounce ability to get to it.
If you opened the chest before receiving the quest, it should already be in your projector room collection! You should be able to tell if it's there or not by checking if Beverly is waiting for you in the room. You'll need to visit an island or trigger a loading screen to get her to head in there. Then, go and project Henry, 8 Years Old.
For visual reference, here's the chest :