diff --git a/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs b/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
index baa01cf5..03b7dd61 100644
--- a/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
+++ b/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
@@ -500,10 +500,25 @@ namespace AcDream.App.Rendering.Wb {
                             if (_dats.Portal.TryGet<DatReaderWriter.DBObjs.Environment>(envId, out var environment)) {
                                 if (environment.Cells.TryGetValue(req.CellStructure, out var cellStruct)) {
                                     data = PrepareCellStructMeshData(id, cellStruct, req.Surfaces, Matrix4x4.Identity, CancellationToken.None);
+                                    // TEMP diagnostic #105 (strip with fix): a null prep here means
+                                    // this deduplicated cell geometry will NEVER render anywhere.
+                                    if (data == null)
+                                        Console.WriteLine($"[geom-null] prepare-null geom=0x{id:X10} env=0x{envId:X8} cs=0x{req.CellStructure:X4}");
                                 }
+                                else {
+                                    Console.WriteLine($"[geom-null] cellstruct-missing geom=0x{id:X10} env=0x{envId:X8} cs=0x{req.CellStructure:X4}");
+                                }
+                            }
+                            else {
+                                Console.WriteLine($"[geom-null] env-read-failed geom=0x{id:X10} env=0x{envId:X8}");
                             }
                         }
                         else {
+                            // TEMP diagnostic #105 (strip with fix): an EnvCell geom id (bit 33)
+                            // whose pending request vanished gets misrouted to the generic path,
+                            // where its hash-derived low bits resolve to nothing -> silent null.
+                            if ((id & 0x2_0000_0000UL) != 0)
+                                Console.WriteLine($"[geom-misroute] envcell geom 0x{id:X10} had no pending request — generic path will null it");
                             // If it's a direct setup or gfxobj, make sure background loads don't abort half-way
                             data = PrepareMeshData(id, isSetup, CancellationToken.None);
                         }
@@ -683,6 +698,9 @@ namespace AcDream.App.Rendering.Wb {
 
                 var renderData = UploadGfxObjMeshData(meshData);
                 if (renderData == null) {
+                    // TEMP diagnostic #105 (strip with fix): the empty substitute is cached in
+                    // _renderData forever -> the object exists but never draws (invisible walls).
+                    Console.WriteLine($"[up-null] upload returned null for 0x{meshData.ObjectId:X10} — caching EMPTY render data (permanently invisible)");
                     renderData = new ObjectRenderData();
                 }