On the screenshot, you can see where the wall is not displayed on the Game tab. So the user draws the wall (the line renderer path is visible while drawing), but then nothing appears.
But if you look at the Scene tab, you can see that the wall was generated and placed at the correct location in the scene. The green point illustrates the same location in both the Game tab and the Scene tab, for point of reference.
For some reason, it seems the camera is not picking it up for display, or something else is going on to where it is not rendered through the view in the app.
I tried to reproduce things as close as possible in the port, but may have accidentally omitted something. For example, in looking at it now, I didn't assign a Wall tag to it. Not sure if that needs to be there for the camera to render it? Maybe it's not a camera issue at all, and something else? Basically, I'm trying to figure out everything that needs to be in place/configured for that wall to also appear in the Game tab, whether it be material requirements, tag requirements, etc etc.
Also worth noting: I switched from polygon to line in the procedural generation, and allow drawing a single wall at a time. Though this shift shouldn't have much to do with the issue as it is visible in the Scene, just not the Game.