Hello. I have Canon 6D and last nightly build ML. After turning off, my camera every 30 sec something doing. LED of SD blinking a few times. And my battery discharge very fast.
Remove battery. Insert battery.
If you are able to reproduce this issue please tell us how.
Not help. Always periodically something do with card.
Delete contents of ML\Settings.
Remove battery, insert card.
Insert battery. Report back.
could it be that you have GPS enabled in canon menu ?
GPS function is know for draining battery when camera is off.
Or maybe this: http://wiki.magiclantern.fm/faq#why_is_the_led_blinking_every_5_seconds