System Protection turned on, but won't save restore points on OS drive

I'm running Windows 10 Pro on a Dell T7910 Workstation housing 8 drives. I have System protection enabled on all of the drives with max usage set to 20% on each drive. I am able to create shadow copies on all of the drives EXCEPT the OS drive. Obviously, that's the most important one when it comes to saving restore points so this is a problem that needs to be resolved. Please don't give instructions on how to turn on System Protection as I have made clear that it's on, and working fine on 7 of my 8 drives. I just can't figure out why my OS Drive keeps showing " There are no Previous Versions Available " while the others show a list of previous versions dating back as far as 2 months.

Any assistance would be appreciated.

Thanks!