Articles not updating on homepage

Here is my site: motorillustrated.com

I have noticed that on the homepage, it takes a day before the latest articles appear in the big box and in the latest news feed (under the galleries section).

I thought it was maybe a caching problem, but when I try to add Wp Super Cache, it tells me it’s unavailable. Could there be a correlation?

Here is a summary of the problem using an exemple.

This article was posted on June 20st: https://motorillustrated.com/2018/06/the-new-2019-volvo-s60-unveiled-this-morning-in-south-carolina/

After it was posted, I could see it in the News section of the site, but I could not see anywhere on the homepage.

After logging in to Wp-Admin, I could see it on the homepage. I could also see it after logging out of wp-admin.

However, when going on another computer or another browser, I no longer saw it unless I logged in.

Then, on the 21st, it appeared on the home page. However, the articles posted on the 21st were not on the homepage. They were in their respective sections however (so if you click News section in menu, then you see article).

Today, the articles for the 21st have appeared, but I can’t see the articles for the 22nd on homepage unless I log in.

In other words, it seems that posted articles appear everywhere except on homepage where they take about a day to appear.

Thanks in advance