Just to confirm, the USB3 connection is USB-C? I have a NVME enclosure which had full USB3 speeds in one cable orientation, but if flipped 180 it would be USB2. I would hope it's not something as simple as that. Can't hurt to try. I know that's the whole point of USB-C, however, that doesn't mean everyone handles things correctly

Must be a feature installed by default by Lenovo. Dell has the exact same thing that you can only control through their "Dell Optimizer" application. They call it "Walk Away Lock" under "Presence Detection". It would automatically lock my computer if I wasn't directly in front of it for more than 60 seconds. A quick search led me to this:

Quote:

The human presence sensor is enabled by default. To disable the function: Open the Vantage app, and then click Device ➙ Smart Assist to turn on or turn off the User Presence Sensing switch. Customize the Zero Touch Login and Zero Touch Lock settings according to your preference. Restart the computer. When the logo screen is displayed, press F1 to enter the UEFI BIOS menu. Select Security ➙ Intelligent Security to customize detailed settings..