Camera has to adjust differently in the middle of the lunar eclipse because there's no more direct sunlight on the surface of the Moon and the whole Moon is in the deep shadow. The little light coming to the middle of the shadow is tinted red and Mn becomes much darker for the duration of the totality of the eclipse. That's why the stars around the Moon are better visible too, Moon is not bright any more. Until the Moon reaches the opposite side of the shadow and becomes bright again, and again camera is not immediately adjusted.