Missing sidebar only on some of the category links

I have an issue with the sidebar, that disappears only from some of the category links. I can’t seem to get a pattern.
This is the link with this issue: http://www.in-turneu.ro/category/europa/romania .
And this is a link with no issues: http://www.in-turneu.ro/category/europa

Can someone identify the difference between the two and why doesn’t the first one work as supposed?

Thank you!