That does appear to be DFU mode. Although it’s a little hard to tell if the LED is blinking yellow due to the LED washing out in the vid, the rate of blinking is consistent with DFU.
Your device is definetly in DFU Mode otherwise it wouldn’t be found by dfu-util -l.
Does the device show up in DevMgr?
If not, you can try to install the DFU drivers manually via zadig
I personally prefer doing things manually instead of reyling on black-box-magic (aka particle docctor ;-))
BTW, an RGB LED has no yellow sub-LED if you see yellow with red then that’s because the red LED and the green LED are lit to produce the yellow colour. So depending on viewing angle you may be able to make out the component colours (red and/or green).
In the video you can clearly see a haze of red on the left side and green on the right side of the RGB LED. Consequently this is considered normal yellow.
Not usually, but there are cases where it can be - mostly half finished updates tend to do that.
Or your code happens to call System.dfu()
Another possibility is when you have the device connected to your computer and the computer defaults to 14400 baud on the USB serial port (that's the magic baudrate for automated DFU flashing).
To exclude the latter you can try powering your Argon with a phone charger rather than off of a computer.
Interesting , if I change the current directory to where dfu-util is located ( C:\Users\deetl\AppData\Local\particle\bin ) and then run particle update I get a different message .
! There are currently no system firmware updates available for this device.
This suggests you have (at least) two different versions of CLI installed.
Check the version of each via particle --version - it should currently be 1.36.3.
If it's considerably lower than that it most likely doesn't know about Gen3 devices yet.
You should remove any older version of CLI via npm uninstall particle-cli and npm uninstall -g particle-cli and for safe measure also via the Windows Installer (Control Panel) and then reinstall the one and only version for your system via the most recent Windows Installer.