USB Copy app causes HDDs to not sleep

[antislow]

After much trial and error, I believe I found the culprit for my HHDs not sleeping.

If I enable the USB Copy app and perform a backup to a usb device, I then eject the USB device and no backups are running or scheduled backups, the HDDs will never sleep after this. Even if I disable the app (without reboot) the drives will not sleep.

If I disable the USB Copy app and reboot the NAS, the HDDs will sleep again when not in use.

I thought I'd report this issue as it didn't seem like the "right" behavior. Just having the USB Copy app enabled, with no USB devices plugged in, would keep the HDDs awake.