It might be something with your forum structure, go to your Administration Panel => Display => Homepage => Structure & Hierarchy

Hello,

Go to Admin Penal -> Display -> Homepage --> Structure and hierarchy Split categories on index : Medium and save.

It showing them all as forums not separating them out.

select medium on the bottom not the top

Did make sure to save the categories as CATEGORIES and not a forum by mistake? go to>>>ACP>>General>>Categories and forums>>Hit the plus icon make a new forum/category

From here there will be a drop down box with options: Forum, Category, Blog. Forum is the default. If you do not change it Category then every section you add will show up as a Forum!