diff --git a/src/naveditor/Editor.cpp b/src/naveditor/Editor.cpp
index 0dd59fce..cf26ddd7 100644
--- a/src/naveditor/Editor.cpp
+++ b/src/naveditor/Editor.cpp
@@ -435,11 +435,11 @@ void Editor::saveAll(std::string path, dtNavMesh* mesh)
 
 	// TODO: this has to be done during navmesh init, not here!!!
 	LinkTableData linkData;
-	buildLinkTable(mesh, linkData);
+	const int tableSize = buildLinkTable(mesh, linkData);
 
 	header.params.disjointPolyGroupCount = linkData.setCount;
 	header.params.reachabilityTableCount = m_reachabilityTableCount;
-	header.params.reachabilityTableSize = (linkData.setCount - 1) * ((linkData.setCount + 31) / 32) + (linkData.setCount - 1) / 32;
+	header.params.reachabilityTableSize = tableSize;
 
 	fwrite(&header, sizeof(NavMeshSetHeader), 1, fp);
 
@@ -458,7 +458,7 @@ void Editor::saveAll(std::string path, dtNavMesh* mesh)
 		fwrite(tile->data, tile->dataSize, 1, fp);
 	}
 
-	std::vector<int> reachability(header.params.reachabilityTableSize, 0);
+	std::vector<int> reachability(tableSize, 0);
 	for (int i = 0; i < linkData.setCount; i++)
 		setReachable(reachability, linkData.setCount, i, i, true);
 
diff --git a/src/naveditor/GameUtils.cpp b/src/naveditor/GameUtils.cpp
index 27283444..b7366bf3 100644
--- a/src/naveditor/GameUtils.cpp
+++ b/src/naveditor/GameUtils.cpp
@@ -98,8 +98,12 @@ void unpatchTileGame(dtMeshTile* t)
 	}
 }
 
-void buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
+int buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
 {
+	// Reserve the first 2 poly groups
+	data.insert_new(); // 0 = technically usable for normal poly groups, but for simplicity we reserve it for now.
+	data.insert_new(); // 1 = DT_STRAY_POLY_GROUP.
+
 	//clear all labels
 	for (int i = 0; i < mesh->getMaxTiles(); ++i)
 	{
@@ -118,7 +122,7 @@ void buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
 	{
 		dtMeshTile* tile = mesh->getTile(i);
 		if (!tile || !tile->header || !tile->dataSize) continue;
-		int pcount = tile->header->polyCount;
+		const int pcount = tile->header->polyCount;
 		for (int j = 0; j < pcount; j++)
 		{
 			dtPoly& poly = tile->polys[j];
@@ -132,16 +136,21 @@ void buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
 
 				if (p->disjointSetId != (unsigned short)-1)
 					nlabels.insert(p->disjointSetId);
+
 				plink = l.next;
 			}
 			if (nlabels.empty())
 			{
-				poly.disjointSetId = (unsigned short)data.insert_new();
+				if (poly.firstLink == DT_NULL_LINK)
+					poly.disjointSetId = DT_STRAY_POLY_GROUP;
+				else
+					poly.disjointSetId = (unsigned short)data.insert_new();
 			}
 			else
 			{
-				auto l = *nlabels.begin();
+				int l = *nlabels.begin();
 				poly.disjointSetId = (unsigned short)l;
+
 				for (const int nl : nlabels)
 					data.set_union(l, nl);
 			}
@@ -149,11 +158,12 @@ void buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
 		}
 	}
 	//second pass
+	// TODO[ AMOS ]: is this necessary?
 	for (int i = 0; i < mesh->getMaxTiles(); ++i)
 	{
 		dtMeshTile* tile = mesh->getTile(i);
 		if (!tile || !tile->header || !tile->dataSize) continue;
-		int pcount = tile->header->polyCount;
+		const int pcount = tile->header->polyCount;
 		for (int j = 0; j < pcount; j++)
 		{
 			dtPoly& poly = tile->polys[j];
@@ -161,6 +171,8 @@ void buildLinkTable(dtNavMesh* mesh, LinkTableData& data)
 			poly.disjointSetId = (unsigned short)id;
 		}
 	}
+
+	return (data.setCount-1) * ((data.setCount + 31) / 32) + (data.setCount-1) / 32;
 }
 void setReachable(std::vector<int>& data, int count, int id1, int id2, bool value)
 {
diff --git a/src/naveditor/include/GameUtils.h b/src/naveditor/include/GameUtils.h
index 83b53738..eb172e71 100644
--- a/src/naveditor/include/GameUtils.h
+++ b/src/naveditor/include/GameUtils.h
@@ -14,7 +14,7 @@ void unpatchHeaderGame(NavMeshSetHeader& h);
 void patchTileGame(dtMeshTile* t);
 void unpatchTileGame(dtMeshTile* t);
 
-void buildLinkTable(dtNavMesh* mesh, LinkTableData& data);
+int buildLinkTable(dtNavMesh* mesh, LinkTableData& data);
 void setReachable(std::vector<int>& data, int count, int id1, int id2, bool value);
 
 #endif // GAMEUTILS_H
\ No newline at end of file
diff --git a/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp b/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
index 2b3db83e..5458eb8d 100644
--- a/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
+++ b/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
@@ -22,18 +22,31 @@
 #include "Detour/Include/DetourCommon.h"
 #include "Detour/Include/DetourNode.h"
 
+static unsigned int getPolySurfaceColor(const dtPoly* poly, duDebugDraw* dd)
+{
+	return poly->disjointSetId == DT_STRAY_POLY_GROUP
+		? duTransCol(duRGBA(240,20,10,255), 170)
+		: duTransCol(dd->areaToCol(poly->getArea()), 170);
+}
+
+static unsigned int getPolyBoundaryColor(const dtPoly* poly, const bool inner)
+{
+	return poly->disjointSetId == DT_STRAY_POLY_GROUP
+		? inner ? duRGBA(32,24,0,32) : duRGBA(32,24,0,220)
+		: inner ? duRGBA(0,48,64,32) : duRGBA(0,48,64,220);
+}
+
 static void drawOffMeshConnectionRefPosition(duDebugDraw* dd, const dtOffMeshConnection* con)
 {
 	float refPosDir[3];
 	dtCalcOffMeshRefPos(con->refPos, con->refYaw, DT_OFFMESH_CON_REFPOS_OFFSET, refPosDir);
 
 	duAppendArrow(dd, con->refPos[0], con->refPos[1], con->refPos[2],
-		refPosDir[0], refPosDir[1], refPosDir[2], 0.f, 10.f, duRGBA(255, 255, 0, 255));
+		refPosDir[0], refPosDir[1], refPosDir[2], 0.f, 10.f, duRGBA(255,255,0,255));
 }
 
 static void drawPolyBoundaries(duDebugDraw* dd, const dtMeshTile* tile,
-							   const unsigned int col, const float linew,
-							   bool inner)
+							   const float linew, bool inner)
 {
 	static const float thr = 0.01f*0.01f;
 
@@ -49,7 +62,7 @@ static void drawPolyBoundaries(duDebugDraw* dd, const dtMeshTile* tile,
 		
 		for (int j = 0, nj = (int)p->vertCount; j < nj; ++j)
 		{
-			unsigned int c = col;
+			unsigned int c = getPolyBoundaryColor(p, inner);
 			if (inner)
 			{
 				if (p->neis[j] == 0) continue;
@@ -147,7 +160,7 @@ static void drawMeshTile(duDebugDraw* dd, const dtNavMesh& mesh, const dtNavMesh
 			if (flags & DU_DRAWNAVMESH_COLOR_TILES)
 				col = tileColor;
 			else
-				col = duTransCol(dd->areaToCol(p->getArea()), 170);
+				col = getPolySurfaceColor(p, dd);
 		}
 		
 		for (int j = 0; j < pd->triCount; ++j)
@@ -164,11 +177,11 @@ static void drawMeshTile(duDebugDraw* dd, const dtNavMesh& mesh, const dtNavMesh
 	}
 	dd->end();
 	
-	// Draw inter poly boundaries
-	drawPolyBoundaries(dd, tile, duRGBA(0,48,64,32), 1.5f, true);
+	// Draw inner poly boundaries
+	drawPolyBoundaries(dd, tile, 1.5f, true);
 	
 	// Draw outer poly boundaries
-	drawPolyBoundaries(dd, tile, duRGBA(0,48,64,220), 2.5f, false);
+	drawPolyBoundaries(dd, tile, 2.5f, false);
 
 	// Draw poly centers
 	drawPolyCenters(dd, tile, duRGBA(255, 255, 255, 100), 1.0f);
diff --git a/src/thirdparty/recast/Detour/Include/DetourNavMesh.h b/src/thirdparty/recast/Detour/Include/DetourNavMesh.h
index 4b6147d1..0ee390df 100644
--- a/src/thirdparty/recast/Detour/Include/DetourNavMesh.h
+++ b/src/thirdparty/recast/Detour/Include/DetourNavMesh.h
@@ -63,6 +63,10 @@ typedef unsigned int dtTileRef;
 /// @ingroup detour
 static const int DT_VERTS_PER_POLYGON = 6;
 
+/// A poly group that is unconnected and considered 'trash'; see [r5apex_ds + CA88B2].
+/// For reference, r2 single player NavMeshes also marked everything unconnected as '1'.
+static const unsigned short DT_STRAY_POLY_GROUP = 1;
+
 /// @{
 /// @name Tile Serialization Constants
 /// These constants are used to detect whether a navigation tile's data