Columns behaviour since update

Hi all,

A few days ago, I updated my Nirvana theme – which I hadn’t done in three months. Since then, the columns on my homepage have a strange behaviour.

While they are supposed to be alined, some of them are not – somehow leaning. Most of the time, it’s the top right and top middle frame. The degree of inclination can also be changing when you refresh the page.

Well, enough words. Here’s the scene of the crime: https://cms16601.apps-1and1.net/

Does anyone have an idea on how correcting this issue?

I would be very grateful! Thanks!

Boyan