I have the same problem with the bios settings refusing to stick. Also on the x370 Gaming 5 motherboard. It loads bios defaults and posts properly every time, but I have to manually load a saved file with preferred bios settings. The problem began when I installed a 3800x and updated the bios.
Can you please explain what you did, what the file linked for download does, etc.?
I just want a bit more explanation before doing this. -- Thanks!