Posts from new (third) category not showing up on homepage

Hi everyone,

I’ve been driven crazy for a couple of hours. I’ve published a post (‘Pièce de monnaie’) in a new category (‘Exceptions’) but it doesn’t want to show up in the blog homepage.
It displays fine in the category page but it’s not showing up on the main page unless I “feature” it when I publish it. This is the only workaround I’ve found.

I know this problem is related to Clean Retina and not from my plugins as my post shows properly when I preview other themes. If I move the post in one of the two first categories (‘Incidents’ & ‘Déceptions’), it works though. I have also tried to delete and recreate the category but it doesn’t work.

It seems blog homepage shows only posts from the two first categories.

Here is the blog URL : http://lenervee.com/

Do you know which way should I enquiry to?

Many thanks!