Gallery Image sorting isn’t working

Hey guys,

my wordpress is on current version. Now the sorting of the Gallery images in a post of the post type Gallery isn’t working. The images in the slider are showing up in completely different order, than i dragged it in the edit window.
I tried to fix it in the functions, but i can’t find a way to get the right order, which the author drags and drops the images.

Is that a known problem, and are there some tips, how to solve this problem?

Best regards – Martin