Upon the first login, the nav drawer is expanded by default. When a user firsts login it is important that the user is aware of the sidebars and then can choose to collapse the sidebar if needed. The status of the nav drawer is always set according to the last status set by the user.
For example :
A user has collapsed the left navigation sidebar then the left sidebar will always be collapsed throughout the Moodle site for that user unless the user manually expands the left sidebar.