Ok, now this is fixed in the new update, but since you’ve mentioned that you probably won’t convert it, here is what you need to fix. The problem is that the functions that set up the edge arrays sometimes try to search outside the grid. This can be fixed with some reorganization and a couple of branches. Remove the Create Walls On Grid Edges function from the Event Graph and Construction Script of BP_GridManager. Instead place it inside the Add Viewport Terrain to Arrays function at this exact spot:
Now, in both the Remove Edges On East And West Side Of Grid and Remove Edges On North And South Side Of Grid functions add a branch to check that the index outputted from the reverse foreach loop is greater than -1
Lastly in the Vector to Index 3D function (also in BP_GridManager) change this number from 1 to 2:
Unless I missed something that should do the trick.