### 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 
Item *item = p_item;
	Item *prev_item = p_item;
	int level = 0;
	while (item) {
		if (item->type == ITEM_LIST) {
			ItemList *list = static_cast<ItemList *>(item);
			ItemFrame *frame = nullptr;
			int line = -1;
			_find_frame(list, &frame, &line);
			int index = 1;
			if (frame != nullptr) {
				for (int i = list->line + 1; i <= prev_item->line && i < (int)frame->lines.size(); i++) {
					if (_find_list_item(frame->lines[i].from) == list) {
						index++;
					}
				}
			}
			r_index.push_back(index);
			r_list.push_back(list);
			prev_item = item;
		}
		level++;
		item = item->parent;
	}
	return level;
}
int RichTextLabel::_find_margin(Item *p_item, const Ref<Font> &p_base_font, int p_base_font_size) {