A little update. The RSS problem goes away (posts are properly formatted) if:
a) One stops using WordPress’ WYSIWYG editor for posts and write directly in HTML editor (which I am hearing is a thing to do no matter what).
b) One does not use (the current version) Fuji’s shortcodes. Which is not a big deal, there’s a lot of ways to add captions to images, etc.
Just wanted to let any visitor know there is a solution if they need one :)