When a sound is played within the session then MRD will trigger PreventUserIdleSystemSleep flag.
"pmset -g assertions" shows
pid 217(coreaudiod): [0x000066e90001852f] 00:00:11 PreventUserIdleSystemSleep named: "com.apple.audio.AppleHDAEngineOutput:1B,0,1,2:0.context.preventuseridlesleep"
Created for PID: 1859.
That flag is removed when the session is closed.
Expected behavior: Remove the flag when the audio output has finished.
Workaround: Edit the session and set "Play sound:" to "Never".