How to reproduce:

1. Go to My Courses or any other "root" view inside a site (messages, calendar events, app settings, ...).
2. Open side menu and click "Help" or "Website". Should open a browser.
3. Go back to the app.
4. Enter a substate (e.g. course contents). Instead of showing back button, the side menu button is shown.

Happens in Android and iOS, smartphone and tablet.