Login redirecting to home page

We want users to be brought back to the page they were trying to access upon login, but in some cases logging in redirects them to the home page instead. Then they have to re-navigate to the page they were trying to access. For some end users this is confusing.

To be more specific: the user (who is not logged in) starts from a joomla article: www.i3health.com/activities/lung-cancer
They click on the "Start Activity" tab, which is a link to a page in a custom module: www.i3health.com/index.php/component/lms/course/index.php?option=com_lms&view=course&layout=content&id=6&lid=25
Access to this page is restricted to registered users, so they are prompted to log in.
Upon login, they are brought to the home page instead of back to the course page.

This problem doesn't happen if they login from a joomla article (such as www.i3health.com/index.php/component/lms/course/index.php ?); in that case they are brought back to the joomla article upon login.

Does CB think the custom module page link is invalid and therefore redirect the user to the home page upon login? How can we correct this problem?

CB V2.1.2
Joomla V3.6.5

CB can not return them to their previous location if their previous location doesn't redirect to the login page with a return url. Joomla com_content does this for category and article access. Joomla menu items should also be handled automatically if it's menu access permissions triggering. 3rd party extensions have to do this themselves if they're manually redirecting to the login page. This means your com_lms extension maybe redirecting to Joomla login internally and is not including a &return=BASE64_URL in that redirect so there's nothing to return to.