This is a great thread. Maybe a bit late for me as I am already pretty committed to using a QNAP TS-879 Pro but the unit is not fully setup and things could go South. Thanks for the added confidence.
Is this regarding fan control from the BIOS, or from within Unraid? I have some control over the fans on my unit in the BIOS.
Awesomeness! I planned to look into this lateron but looks like the initial lifting has already been done.
I briefly had Win10 running on the system just to poke around - there it was an issue. It's not replicated with Unraid. (HW differs between our boxes though.)
No answer to your issue. Before starting with Unraid, I removed my DOM. It was sitting on a USB 2.0 header, secured with a glob of sticky compound and a plastic clip.