This is a Coursera problem. Supposedly they have a solution in the works, but in the meantime you have to contact the Help Center and they can fix this for you. Here are the instructions from the course staff:
Ask them to contact Coursera Chat and to be specific with the agent in explaining their issue. It will help greatly if they would share a screenshot with the agent as a proof that they, in fact, did get a passing grade, asking the agent to manually update the assignment completion.