This seems natural to me, some strains just do that almost as if they are programmed for a rest. Transpiration plays a role of course.
I’ve been recommended silica as a way to keep plants praying for longer periods of time, but I’m of the belief that if they want a break let em have it.
Edit: At first I thought you were saying leaves DROPPED at the same time daily. Now that would have been a head scratcher!