The install script will disable backports on install for the RPi now. I didn't dig into but a fresh Raspberry Pi OS install will have apt pinning at 100. The RPi doesn't need backports enabled anyway. So, I would recommend that all RPi users disable backports.
My openmediavault-local.pref file has apt pinning 995. Should I change it to 100? This is on a fresh 64bit PiOS install.