Website content different for Mobile than for PCs

I found out a very strange behaviour that one of you guys might be able to explain or help me solve it.

I just launched a new blog which works well on PC and Mac but for some reason which baffles me the content displayed on the iPhone or any mobile I suppose is not up to date. It displays a very old post.

And that happens only for the home page. The content can be access directly without a problem from the iPhone

Any idea what I should do?