I just reinstalled windows 10. Clean install, from a newly created boot USB flash drive, with all settings reset to default before restarting (they are now synced), wiping all partitions and reinstalling. After it installed I updated it, installed my drivers including RME Babyface and did the exact same test. There is no change, the computer can enter sleep normally, and as soon as both of the settings in the following picture are chosen, the computer cannot sleep. I have two computers, completely different configurations, with two different RME Babyface interfaces. There is nothing running on either computer when I test. I have reinstalled windows on one of the computers, but I can do the same on the other one, if needed to confirm.
This is what Command Prompt shows:
the computer with newly installed windows 10:
EVGA GeForce GTX 1070
other computer also running windows 10:
MSI P6N SLI Platinum
Intel Core 2 Duo E6600
MSI GeForce GTX 1030
The only things similar between the computers are the same Nvidia driver for the GPUs and Logitech driver for the mice.
Edit: There is nothing connected to the MIDI in connector, if that makes any difference.
Edit 2: Besides the different hardware, which might not be relevant, since I have two different configurations that show the exact same result, another variable is windows 10 versions and updates. This could explain why the problem is not reproducible on your end and why nobody ever reported such behavior. I noticed big differences between windows 10 major updates. Is it possible that something in windows 10 is causing this problem?