Lo-Fi Games

Basically, the problem that I have encountered is when building additional walls to my outpost to create a second "compound" of sorts, the new walls either lack collision or people can walk right over them like an extension of the terrain. The original wall section is fine, it's just the new parts that are causing issue.

I don't know if it's the direction the walls are facing that may be the issue, but nonetheless it's still a rather strange issue

Your walls are indeed facing the wrong way. Chris stated in the read me for 0.40.2 that this would cause problems. Try tearing down the walls, building them correctly and checking if the problem remains.