try detecting instance placeholders during packed scene instantiation

scene/resources/packed_scene.cpp

@@ -314,6 +314,17 @@ Node *SceneState::instantiate(GenEditState p_edit_state) const {
 					ERR_FAIL_INDEX_V(nprops[j].value, prop_count, nullptr);
 
 					if (nprops[j].name & FLAG_PATH_PROPERTY_IS_NODE) {
+						if (node->get_scene_instance_load_placeholder()) {
+							// nodes might not exist yet, so we skip deffering nodepath resolution to placeholder instantiation
+							// this does not solve arrays problems, and creates issues with external node referneces
+
+							uint32_t name_idx = nprops[j].name & (FLAG_PATH_PROPERTY_IS_NODE - 1);
+							ERR_FAIL_UNSIGNED_INDEX_V(name_idx, (uint32_t)sname_count, nullptr);
+
+							node->set(snames[name_idx], props[nprops[j].value], &valid);
+							continue;
+						}
+
 						uint32_t name_idx = nprops[j].name & (FLAG_PATH_PROPERTY_IS_NODE - 1);
 						ERR_FAIL_UNSIGNED_INDEX_V(name_idx, (uint32_t)sname_count, nullptr);
 
@@ -358,7 +369,7 @@ Node *SceneState::instantiate(GenEditState p_edit_state) const {
 							value = setup_resources_in_array(set_array, n, resources_local_to_sub_scene, node, snames[nprops[j].name], resources_local_to_scene, i, ret_nodes, p_edit_state);
 
 							bool is_get_valid = false;
-							Variant get_value = node->get(snames[nprops[j].name], &is_get_valid);
+							Variant get_value = node->get(snames[nprops[j].name], &is_get_valid); // this will always be false for InstancePlaceholders because set has not been called, resulting in un-typed arrays
 
 							if (is_get_valid && get_value.get_type() == Variant::ARRAY) {
 								Array get_array = get_value;