iMac Pro Bootcamp Blackmagic mini Recorder

I have installed Windows 10 Pro with Bootcamp on both my iMac Pro1,1 2017 and Macbook Pro13,3 2016. The Blackmagic UltraStudio Mini Recorder is connected via the Apple USB-C Thunderbolt 2 adapter and works fine on OSx High Sierra and the Windows 10 Bootcamp on the Macbook Pro *** but not *** on the Bootcamp iMac Pro. The Mini Recorder ***light turns off*** right after the Windows 10 selection (boot) but does not turn back on seconds later (as it does on the Macbook Pro, hence works thereafter in the session). I have reinstalled both machines with no luck. I suspect there is a driver problem related to the USB-C hardware of the iMac Pro with the Bootcamp. Again, the mini recorder works fine on that machine using High Sierra, it's not a cable problem.

I have all latest drivers and Blackmagic software on both the Mac High Sierra system and the Bootcamp running Windows 10 Pro (I am an IT professional). I have tested the UltraStudio on another recent iMac (not the Pro) and it works on both environments. It's definitely a iMac Pro - Bootcamp issue with the power being cut on the Thunderbolt 3 (USB-C) right after the initial switch (option key) on the Windows partition. The UltraStudio light shuts down and does not come back (i.e. no power being sent to the USB-C) with Bootcamp. The power and connection works fine under the High Sierra partition.

Has anyone successfully used the UltraStudio mini Recorder on an iMac Pro running Windows 10 ? I am not sure it's a iMacPro specific driver problem with external USB-C power or a Blackmagic driver issue.

I need the Bootcamp-Windows 10 for reliability with OBS streaming with multi cams.