I'm not quite sure but I believe since installing DR the spin-down timer has been broken or disabled by DR, i.e. the disc will endlessly spin although there's no access by the OS. Originally OS X spins down the drive if it's not needed.
I also have this problem. MacOS High Sierra.
Workaround: quit discrotate.
I suppose either it resets the spindown timer on exit or when running just repeatedly sets the speed thus preventing spindown.
BD Drive: HL-DT-ST BD-RE BE12LU38:
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I also have this problem. MacOS High Sierra.
Workaround: quit discrotate.
I suppose either it resets the spindown timer on exit or when running just repeatedly sets the speed thus preventing spindown.
BD Drive: HL-DT-ST BD-RE BE12LU38: