I wonder if it's some kind of lens flare, if such a thing is possible when taking these kinds of images.
It's still pretty damned amazing for an infinitesimally small part of the universe.
It's just that we can only see and interact with a finite portion of this universe, and sadly, over time this portion will shrink in relative terms.
In the distant past, more of the actual universe was visible. The distances between galactic clusters was smaller.
In the vastly distant future, our galaxy might be the only one visible. The rest of space will simply be empty, light stretched out so much that it's nothing more than faint background noise.