Display error on custom layout blog page

Hi,
we created a custom layout for our blog page and now we’re getting a displaying error, some kind of container above the color section that should not be there. I can’t figure out, where it comes from, could use some help there, please.

I think it’s obvious, but I marked the spot anyway

View post on imgur.com

the page template used on the custom blog page is also used on numerous other pages of our site, there it works just fine.

As always, thanks a lot for your help in advance!

regards,
matthias