Gallery scrolling

Hi,

I have a strange issue here with my pic gallerys. It′s absolutly done in the same way, but in one gallery after clicking for the next pic, the hole page is loading again and jumps to the top (https://hartz4kontakte.com/schlagzeilen/schlagzeilen1/), in the other example the pics can be browsed fluid without scrolling and jumping to top (https://hartz4kontakte.com/schlagzeilen/schlagzeilen-6). Why is this difference and what can I do to have it all like the last one? Thank you so much.