How fix camera clipping through portal

Godot Version

Godot 4.4.1

Question

The camera clip through the portal before teleporting.
To create portals as a reference, I used this repository: GitHub - Donitzo/godot-simple-portal-system: A simple portal system for viewport-based portals in Godot 4.

Can anyone tell me what the problem is?

I tried: Use csgbox with culling off instead of mesh

Matrix magic, which I don't understand (that's probably the problem)

Maybe the problem has to do with forgetting to turn on the nodes?

Here’s the project repository: GitHub - nik0mi/vohis