Category base permalinks not working??

I see you have added support for category base permalink. When I set “media” as the MCM Category base, I would expect that when I upload a media item, the permalink would look like: https://www.myuwebsite.com/media/picture1.jpg. However, the permalink actually is:
https://www.myuwebsite.com/picture1.jpg.

I am not sure of what I am doing wrong.

Thank you in advance.

Robin