My question is basically the same as in EliteBook 8470p shutting off charging from USB charging port , but for a different device.
I shutdown the device, plug off the power supply of my docking (thunderbolt), and the network port is still blinking.
Even when I plug the docking station when the notebook is off, it gets power from the notebook.
I think I found the option in the BIOS setup and disabled it, but it doesn't change anything.

In case the photo is not visible: The option I disabled is "USB Legacy Port Charging"
After a weekend with my notebook turned off on the docking without external power supply, the battery is so low that it shows a battery warning after logging in.
Did I miss anything to disable this USB power when off?