Having problem with my news section (padding / margins)


I hope this is the right board for my question. I have built up my website with beaver builder plugin so far. Everything was fine for over one year, but then I made a change in the CSS - i think. It seems like the first and the sixth news row doesn’t have the same margin as the others… It’s a bit strange, because when I publish a new post, it has the same problem as the post before. I mean the problem slips up… Hopefully somebody can help me.
I’m not a rookie in programming, but I can’t explain that problem… Anyone with an idea??? I would be so glad <3

Website: https://bipolar.berlin

take a look at the picture, I hope you see what I mean…

It can also be, that the problem arrived with wordpress 5.0 … anybody with the same experience?

I have uploaded an old css backup, but nothing changed. I think it’s not the CSS… =/