Git repos on HFS disk are corrupt when accessed from windows

I'm using bootcamp on a new macbook pro. I've installed HFS+ in windows in order to access my mac os drive.

When I try and use a git repo from the mac os drive, it reports that object files are empty. If I reboot in Mac OS they are all fine and I can see the files have content, but using HFS+ in Windows they are reported as 0 bytes.

The object files are inside the .git folder and are named as just a hex value without any extension. eg MyProject/.git/objects/4c/0bcf8c6ea350dd582023ad3b2a3cd8d4682aee

Other files are ok, it just seems to be these and I can't find any reason why?