Configuration details:
Dell Latitude 5520 laptop with 11th Generation I7, 16G memory
System only supports S0 low power idle (S1, S2 & S3 sleep modes not supported) see uploaded powercfg image
W10 Pro 20H2, Macrium Reflect 7.3.5758
I've deselected the display backup notifications under Edit Defaults Advanced options...

Afterwards, I created new XML definition file and schedule.
Using WTS to schedule/run an incremental at 6:00am. The status of the notebook at the scheduled time has a logged on user and the screen is closed.
Per Task Schedule the job starts ~6:00am

But the task hangs until I open the Laptop & unlock the screen at which time I see the dialog box...

Am I missing something, or is this a bug/issue?