A new process for course module deletion is introduced in MDL-54751. This issue has been created to allow the mobile team to make this change too, provided the solution put forward in MDL-54751 is accepted.

As it stands, MDL-54751 has left the deletion process for mobile as it was; the deletion of modules happens immediately in course/externallib calls (and can take a long time). See diff here. To use the new adhoc approach, simply use the original function - course_delete_module().