I lock my modules so the students will complete them sequentially. Two students claim that the modules are still locked for them. When I check, the modules are open, other students have completed the same assignments and yet it appears that the affected students have completed the pre-req module yet the subsequent module is still locked for them. The pre req module is a Discussion and when I click on their names, they've posted and responded to students in the Discussion so they as other students should be able to open the next modules. But they can't. What are we missing?