Level1 Tech KVM and ZMK Keyboard Firmware (SlickMK), Scroll Lock hotkey not working

I have one of the DisplayPort 1.4, 4-port (single monitor) KVMs from Level1Tech. I’ve had it for a few years, so I think it might have been the first run.

Anyway, it’s worked really well for years. I even got some Club3D short cables this year and was able to get 120Hz/4k on the Windows box, so super cool.

This week I’m giving a split keyboard a try; the SlickMK (which is a wireless Ergodox layout using the ZMK firmware).

It works with the KVM, but the Scroll Lock hotkey doesn’t seem to work at all. I double checked with xev in Linux and my keyboard firmware is reporting Keycode/78, NoSymbol (same as the scroll lock key on the two other keyboards that work with the KVM)

The USB receiver is plugged into the exact same port as my other keyboards. I used an online N-KeyRollover tester and the keyboard only appears to register 6 total keys (so I suspect it’s still in BOOT mode and not USB input mode?)

Has anyone else had issues with the ZMK firmware and the Level1Tecj KVM? I’m using the symbol SLCK from the ZMK documentation. You can see it here on the layer 2 bindings: