### Godot version

v4.0.beta16.official [518b9e580]

### System information

Windows 10

### Issue description

`RichTextLabel` with `threaded` enabled may crash the game or show the following warning if the node is in another scene:

```
W 0:00:03:0802   test.gd:12 @ load_with_scene(): A Thread object has been re-started without wait_to_finish() having been called on it. Please do so to ensure correct cleanup of the thread.
  <C++ Source>   core/os/thread.cpp:76 @ start()
  <Stack Trace>  test.gd:12 @ load_with_scene()
                 test.gd:6 @ load_items()
                 test.gd:26 @ _on_button_pressed()
```

It may crash the game (without any warning) if it's added directly.

In `v4.0.beta15.official [4fa6edc88]` I was able to reproduce the same warning on my project but I can't reproduce it in the attached MRP. I get a different error and will crash too if the node is added directly:

```
E 0:00:03:0019   remove_from_group: Condition "!E" is true.
  <C++ Source>   scene/main/scene_tree.cpp:157 @ remove_from_group()
```


### Steps to reproduce

Click on the  `Load with scene` or `Load with node` buttons in the attached MRP until it shows a warning/error or crashes. It may take a while.

### Minimal reproduction project

[add_chid_bug_b16.zip](https://github.com/godotengine/godot/files/10521402/add_chid_bug_b16.zip)

continue;
						}
						int dif = table->columns[i].width - table->columns[i].max_width;
						if (dif > 0) {
							table_need_fit = true;
							table->columns[i].width = table->columns[i].max_width;
							table->total_width -= dif;
							total_ratio -= table->columns[i].expand_ratio;
						}
					}
					
					remaining_width = available_width - table->total_width;
					if (remaining_width > 0 && total_ratio > 0) {
						for (int i = 0; i < col_count; i++) {
							if (table->columns[i].expand) {
								int dif = table->columns[i].max_width - table->columns[i].width;
								if (dif > 0) {
									int slice = table->columns[i].expand_ratio * remaining_width / total_ratio;
									int incr = MIN(dif, slice);
									table->columns[i].width += incr;
									table->total_width += incr;
								}
							}
						}
					}
				}
				
				idx = 0;
				table->total_height = 0;
				table->rows.clear();