Yes I don't like it. It spoils the finale of the book. It takes a while until it is clear what kind of monster it is. Already on the cover.
Then also the deus ex machina moment to save them is spoiled.
Only way to make it worse would be to put the diary on it with the name Tom Riddle written on it.
As someone who avoids trailers to not spoil movies, this is bad Imo.