Added missing ex

dist/preview release/babylon.max.js

@@ -23826,7 +23826,7 @@ var BABYLON;
                     }
                     catch (e) {
                         if (onerror) {
-                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename + ' (Exception: ' + e + ')');
+                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename, e);
                         }
                         scene._removePendingData(loadingToken);
                     }

src/Loading/babylon.sceneLoader.js

@@ -142,7 +142,7 @@ var BABYLON;
                     }
                     catch (e) {
                         if (onerror) {
-                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename + ' (Exception: ' + e + ')');
+                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename, e);
                         }
                         scene._removePendingData(loadingToken);
                     }

src/Loading/babylon.sceneLoader.ts

@@ -158,7 +158,7 @@
                         }
                     } catch (e) {
                         if (onerror) {
-                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename + ' (Exception: ' + e + ')');
+                            onerror(scene, 'Unable to import meshes from ' + rootUrl + sceneFilename, e);
                         }
                         scene._removePendingData(loadingToken);
                     }