It does not seem to be a cable. It works when connecting directly to the computer. I tried another cable 10Gbit superspeed, still the same results...
My HDMI switch supports the switching between connections using the keyboard hot keys (Ctrl,Ctrl, 1-4), so I guess it might be doing some tricks for ...

If I connect my new picokvm to my KVM switch, it powers up but does not show the USB connected status, and the keyboard/mouse not working. If connect picokvm directly to the server it works fine.

My old DIY pikvm does not have that issue and works when connected to the KVM switch. Anything can be ...