Just another observation: the behavior of the black optimizer seems to be related to the content displayed immediately prior to a dark scene. For example, you can watch an opening outer space scene with deep black levels. The first time the scene is played, there is a lag before the black optimizer kicks on. This scene is at the beginning of a chapter. If you go to the beginning of the chapter while the dark scene is still playing, the lag is reduced. Move forward to a lighter scene, then go back to the beginning of the chapter, the lag lengthens again.