L1 KVM - USB won't follow port selection

I have SQ1007387 KVM (1.4 Display Port KVM Switch - Dual Monitor - Two Computer) connected to my PC (b450, RTX 2070, Windows 11) and MBP 16" M1. When I switch the port by LCtrl-LCtrl-{1,2} I have to follow it with Lctrl-Lctrl-U or otherwise USB won’t switch. I tried LCtrl-LCtrl-F7 (two beeps, then one beep for enabled, presumably) but the problem persists. This definitely used to work - is there any way to factory reset the KVM?

More broadly, is there any manual for this specific KVM model?

hmm… @wendell ?

Unplug tbe kvm from power and usb for a solid minute rhen retry the follow sbortcut