I just checked the Advanced options and yes, the display backup notification delay for 20 seconds is still enabled.
I believe someone else posted somewhere else on the forum they encountered this same missing dialog.
Here's that screenshot you asked for.
Hm, this is interesting. This may be a bug. With the Reflect main interface open, Print Screen key does NOT work. When Reflect main interface is closed, Print Screen key resumes working. I will have to restart the PC after updating and see if it's maybe some kind of memory issue or a possible repeatable bug in the Reflect software.
I'll just type in the pertinent information from the tab.
Schedule: At 9:45 AM every X. (Current schedules are for Thursday, Friday, and Saturday, all at 9:45 AM, all executing at 9:50 AM)
(For today, Saturday 10-17-2020) Next time run: 10/24/2020 9:45 AM
Last time run: 10/17/2020 9:45 AM
Last result: 0x00 Successful
User account: SYSTEM
EDIT: I updated Reflect to 7.3.5289 and restarted my PC. The Print Screen key STILL does NOT work for me when the Reflect main interface is opened. It DOES work when the Reflect main interface is closed.