Don't copy transform components into linked prefab

Author: vkovec

com.unity.formats.fbx/Editor/ConvertToNestedPrefab.cs

@@ -450,6 +450,10 @@ public static GameObject Convert(
             // replace hierarchy in the scene
             if (!isPrefabAsset && toConvert != null)
             {
+                // keep the transform of the root of the prefab instance the same
+                var jsonTransform = EditorJsonUtility.ToJson(toConvert.transform);
+                EditorJsonUtility.FromJsonOverwrite(jsonTransform, fbxInstance.transform);
+
                 Undo.DestroyObjectImmediate(toConvert);
                 Undo.RegisterCreatedObjectUndo(fbxInstance, UndoConversionCreateObject);
                 SceneManagement.EditorSceneManager.MarkSceneDirty(fbxInstance.scene);
@@ -873,8 +877,12 @@ internal static void CopyComponents(GameObject to, GameObject from, GameObject r
                 // ignore FbxPrefab (when converting LinkedPrefabs)
                 // Also ignore RectTransform, since it is not currently possible to switch transforms
                 // in a prefab.
+                // Don't need to copy regular transform either as the values should already be correct in the FBX.
+                // Furthermore, copying transform values may result in overrides in the prefab, which is undesired as if
+                // the transform is updated in the FBX, it won't be in the prefab.
                 if (fromComponent is UnityEngine.Formats.Fbx.Exporter.FbxPrefab ||
-                    fromComponent is RectTransform)
+                    fromComponent is RectTransform ||
+                    fromComponent is Transform)
                 {
                     continue;
                 }