Hi. I dont know any fix, but yeah, light leaking is my biggest with vxgi. You can take a look /issues/33, there are some “insights” and tips you can try.
I dont understand how exactly VXGI works but would it be posible to somehow tell the inner voxels (and determine inner voxels) to just absorb all light? Light leaking with wall thick only two voxels isnt bothering me that much but 1m thick wall with lot of inner voxels leaking light is disappointing. Well i hope one day find out a solution. I wish him best luck.