### Godot version

master ([06ccbfe](https://github.com/godotengine/godot/commit/06ccbfe8eec6e840db3df2360dc2804386f940b8))

### System information

PopOS 22.04

### Issue description

Sometimes the doc page is broken when the engine is closed and then restarted.
Closing the doc and opening it again fixes it.

![2023-05-27_22-15](https://github.com/godotengine/godot/assets/3624853/ed202a55-03e8-420a-bc1c-ccfc7f7cd02a)


### Steps to reproduce

- Open a documentation page for any node
- Restart Godot

### Minimal reproduction project

NA

EDIT : Added the commit hash @Calinou 
line = p_text.substr(pos, end - pos);
		}
		if (line.length() > 0) {
			if (current->subitems.size() && current->subitems.back()->get()->type == ITEM_TEXT) {
				
				ItemText *ti = static_cast<ItemText *>(current->subitems.back()->get());
				ti->text += line;
				_invalidate_current_line(main);
			} else {
				
				ItemText *item = memnew(ItemText);
				item->text = line;
				_add_item(item, false);
			}
		}
		if (eol) {
			ItemNewline *item = memnew(ItemNewline);
			item->line = current_frame->lines.size();
			_add_item(item, false);
			current_frame->lines.resize(current_frame->lines.size() + 1);
			if (item->type != ITEM_NEWLINE) {
				current_frame->lines[current_frame->lines.size() - 1].from = item;
			}
			_invalidate_current_line(current_frame);
		}
		pos = end + 1;
	}
	queue_redraw();
}
void RichTextLabel::_add_item(Item *p_item, bool p_enter, bool p_ensure_newline) {