There is a black edge under the vr rendering camera.

Change the perspective window to camera view, and then use SHIFT+F, which is the fast forward key to display the security box. The security box shows the size and what you see in the real rendering.

Besides, there are two possible reasons for your mistake. One is to modify the manual cutting option under the panel; The other is that the camera angle is not adjusted well, resulting in light leakage.

It should belong to the latter, and the camera height and field of view are unreasonable. According to your drawings, just put the camera height at 900 900-1200MM, and don't let the camera line of sight touch the wall in the top view.