Description
Portals can be spawned anywhere as long as the line trace hit is successful. This can lead to odd locations when spawned. i.e. A portal half under the floor or in a wall. This also means that portals can be spawned on top of eachother, which can lead to unintended behavior described in #1.
A good solution is to ensure portals are snapped to a grid and also have logic in place to prevent spawning op top of eachother as well as half through surfaces.