In Process Simulate, top view is not really top view, the side geometry of objects is slightly visible.
This is designed behavior to prevent singularity in the viewing matrix.
As workaround, on the graphics window select the gear icon located at the lower left corner.
This will open the "Graphic Viewer settings".
Go to Navigation tab and change "Rotation method" to "Rotate object (Vis method)".
After this change you will get an accurate top view.
Notes