It works, but whats this?

[Cyber-Shinobi]

trafficstars

[timxor]

lol 😂

[ehx-v1]

Looks like polygons are rendered that would be visible through the seamless portal from within the structure. Either that, or you somehow loaded 2 stages at once, causing them to overlap weirdly. (It might be something else, those are just logical conclusions from general basic knowledge on seamless portal geometry and raytracing.)