This issue has been resolved in 3.1.4 of the iOS app. Please download the update and you should not longer experience this problem.
iPhone, iPad and iPod Touch users of Mobile Learn are encountering an issue where their "group" options disappear if they are enrolled in multiple groups. If you are only enrolled in one group, you will be able to navigate to your "Groups" menu option (either under "Tools" > "Groups" or under "Groups" in your main menu), select your Group name, and find all of the tools associated with that Group (like Group Discussion Board, Tasks, etc.). However, there is currently an error in the Mobile Learn app that causes all of your groups to disappear/become inaccessible in the app if you are enrolled in multiple groups.
Our engineering team is working on this issue right now and we hope to release a fix soon in a future update of the Mobile Learn app. We will update this article once the issue has been resolved.