Looks like your PartMgr service failed to update the registry hive. If you still insist on risking I syggest you the following. Boot from Parted Magic CD again and shrink the wrong reported partition for 500MB. Apply changes. When done restart to Windows. Does it report now correctly?
If not boot again to Parted Magic and increase the size for 500MB. Restart to Window. Does it report properly?
Also when you run DiskPart what sizes does it show?
Another possible cause - partition has been moved but file system not. DiskPart could help here.
Next time you need to perform resize with guarantee use Paragon Partition Manager 11 Server Edition:
www.partition-manager.com This tool never let me down.