My m15 recently started failing to automatically hibernate. I have had sleep disabled and automatic hibernate set in power options to 10 min and at 5% critical battery level. Very recently experienced issues with both - on one occasion battery ran down to zero and laptop shut down, yesterday I left if on battery on the desk without explicitly hibernating only to find out later it was on all the time and almost ran out of battery. Both auto-hibernate functions used to work as expected until recently. Any ideas what could be causing this or how to fix? Many thanks.