Unable to power down FW13

I’m trying to replace my mainboard but the red LEDs keep flashing, indicating the laptop is still on. I’ve tried the normal shutdown command (Start->Power->Shutdown) and forcing a hard power off (holding power for 8s (or 12 or 20ish)) but the red LEDs won’t stop.

Windows 10
FW13 1135g7
Bios 3.19

Is there a hard(er) power off option that I’m missing?

They indicate the chassis intrusion detection switch is active/no input cover is installed.

Its more a safety to let you know the mainboard has power. You can safely proceed to disconnect the battery as per Step 7 Mainboard Replacement Guide - Framework Guides