diff --git a/contrib/mmap/src/TerrainBuilder.cpp b/contrib/mmap/src/TerrainBuilder.cpp
index e0fbeb974fe..18f62ede7fe 100644
--- a/contrib/mmap/src/TerrainBuilder.cpp
+++ b/contrib/mmap/src/TerrainBuilder.cpp
@@ -766,9 +766,12 @@ namespace MMAP
                     float inDist  = -1.0f;
                     if (it->IsUnderObject(v, up, isM2, &outDist, &inDist)) // inDist < outDist
                     {
-                        //if there are less than 1.5y between terrain and model then mark the terrain as unwalkable
-                        if (inDist < 1.5f)
+                        // If terrain is under wmo, mark terrain as unwalkable
+                        // If there are less than 1.5y between terrain and m2 then mark the terrain as unwalkable
+                        if (!isM2 || inDist < 1.5f)
+                        {
                             terrainInsideModelsVerts[t] = inDist;
+                        }
                     }
                 }
         }