Don't be panic yet. If I understand correctly, your Mom is a refuge claimant? Anyway, misrepresentation or not, it depends on that if the wrong information on the form is material or not, which means that was the marital status on the form actually a concerning factor that would lead the VO wrongfully issue the Visitor VISA to your Mom in the first place or not. Let's say if a married woman will be a negative factor to issue the visitor VISA, then what your mom did, intentionally or not, is in fact a misrepresentation, otherwise there isn't any grounds for misrepresentation. And actually, a lot single women did the opposite to claim they were married to show the VO that they had some ties with their countries, that is in fact definitely a misrepresentation.
Although, there may not a misrepresentation, your mom will still need to provide CIC an explanation letter and any other backup documents for this incident.