As shown, overlooking the view zooms to a minimum, you can see the entire grid, creating a light volume, after amplification beyond this grid, will disappear, which is what the problem is. In udk when there is this problem.
I can see the issue here and have submitted a bug report (TTP: 349539) for the volumes not scaling beyond the grid. I could get it render in a single viewport if I scaled the volume non-uniformly.
Using a volume this size if probably not the best practice though as you have a lightmass volume covering over 5k area.
Thank you, because I saw the U3D grid is a wireless scaling, but UE is not a wireless scaling, this in the creation of the so-called big world volume box over grid is inevitable, but beyond will disappear, solve the hope authorities to consider this question.