I have a scene with a hollow box with a hole and movable directional light. Box walls are 64cm thick. LPV bias is 2, other parameters are default. The light enters the box then is reflected on opposite walls by LPV. There is no other lights in the scene.
LPV isn’t the best dynamic GI solution out there so it has some limitations like the one you are seeing. In some cases it can be difficult to keep the volumes out of unwanted areas and you’ll see light bleeding when the volume is larger than the mesh. You can minimize this by decreasing the size in PP volume settings but still dont expect anything perfect if you are planning to use it for interior lighting.
