Have you updated the firmware recently? https://us.starlabs.systems/blogs/news/firmware-update-announcement-25-05
They’ve fixed a lot of ACPI and power issues with various models, including the mk7: https://github.com/StarLabsLtd/firmware/issues/139
Try running
sudo shutdown -h now
and see if it still does the same thing.If so, try forcing ACPI actions like so and see what happens: https://askubuntu.com/questions/125844/shutdown-does-not-power-off-computer#127022
I know this an ACPI tables issue, but there’s a wide variety of debug steps to figure out which one.