1. Drop a wall segment 2. Right click to cancel placement mode, walk away 3. Drop a wall segment again - you need two clicks to determine start and end point. 4. Swap weapons, walk away 5. Place what should be the start point for new segment 6. The wall is placed with its start point where the previous segment's end point is, and the end point where you just clicked. In other words, swapping weapons doesn't do the same thing as right clicking after placing a wall. And it keeps happening. So there you go, now someone needs to fix this and we're golden.