1. In 3ds Max, create a box with dimensions 5000 by 5000 by 5000.
2. Align the bottom center of the box to the origin at coordinates (0, 0, 0).
3. Set the ambient light in the rendering settings to red with a brightness of 99999.
4. Create a new camera to observe the ground center of the box at the origin coordinates.
By following the above steps, you will achieve a red dot that is invisible in V-Ray rendering but visible in Vantage rendering.
It’s hard to fix this issue without creating other problems.
I think another solution you can try is to add some thickness to your walls/box in order to avoid this light leak from the environment.