Had another one today, 13" i5/16/512/space gray. Nothing attached, not even power. Booted from clean shutdown after being shutdown for a couple of days. Entered my password to login, then got the SMC/BridgeOS KP. It rebooted, I logged in, got the error report and sent to Apple.
ETA: This is the only time I get "the" KP on this machine, logging in after clean shutdown after it's been sitting for a few days with nothing attached. Have yet to have one while logged in/working on the computer.
ETA2: Experiencing very erratic battery readings today as well. Before KP when logging in, 97%. After the KP reboot, 99%. 10 minutes after logging in, 93%.