As it currently stands, category is hard coded into NodeBB. It will require a lot of work to make the paths custom, but it is a planned feature. So, you will either have to just not change the path or get somebody to change all of the hard coded areas that need to be notified in the site code.
@julian Thank you for your answer, and yes, that could be where the problem comes from.
I have these plugins on : default composer, alignment, markdown, simple spoiler.
PS. But I don't have the "redactor plugin" if by that you mean a wysiwyg editor.
