Read the statement by Michael Teeuw here.
UNSOLVED Black screen a few minutes after start MM
I have a automation that MM start at morning. Everything works great but when i turn off screen from MM-remote and try turn it on after few minutes monitor turn on but i have a black screen. I must connect to raspberry from vnc, “click” on mm and everthing work to next restart raspberry. I noticed that when i run rpi i have a cursor on mm but he disappears when i conect from vnc.
@kedzior sounds like the pi screensaver is still enabled