### 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 *_get_prev_item(Item *p_item, bool p_free = false) const;
	Rect2 _get_text_rect();
	Ref<RichTextEffect> _get_custom_effect_by_code(String p_bbcode_identifier);
	virtual Dictionary parse_expressions_for_values(Vector<String> p_expressions);
	void _draw_fbg_boxes(RID p_ci, RID p_rid, Vector2 line_off, Item *it_from, Item *it_to, int start, int end, int fbg_flag);
#ifndef DISABLE_DEPRECATED
	// 
	bool _set(const StringName &p_name, const Variant &p_value);
#endif
	bool use_bbcode = false;
	String text;
	void _apply_translation();
	bool fit_content = false;
	struct ThemeCache {
		Ref<StyleBox> normal_style;
		Ref<StyleBox> focus_style;
		Ref<StyleBox> progress_bg_style;
		Ref<StyleBox> progress_fg_style;
		int line_separation;
		Ref<Font> normal_font;
		int normal_font_size;
		Color default_color;
		Color font_selected_color;
		Color selection_color;
		Color font_outline_color;
		Color font_shadow_color;
		int shadow_outline_size;
		int shadow_offset_x;
		int shadow_offset_y;
		int outline_size;