### 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 
ItemFade *fade = nullptr;
			Item *fade_item = it;
			while (fade_item) {
				if (fade_item->type == ITEM_FADE) {
					fade = static_cast<ItemFade *>(fade_item);
					break;
				}
				fade_item = fade_item->parent;
			}
			Vector<ItemFX *> fx_stack;
			_fetch_item_fx_stack(it, fx_stack);
			bool custom_fx_ok = true;
			Point2 fx_offset = Vector2(glyphs[i].x_off, glyphs[i].y_off);
			RID frid = glyphs[i].font_rid;
			uint32_t gl = glyphs[i].index;
			uint16_t gl_fl = glyphs[i].flags;
			uint8_t gl_cn = glyphs[i].count;
			bool cprev_cluster = false;
			bool cprev_conn = false;
			if (gl_cn == 0) { 
				cprev_cluster = true;
			}
			if (gl_fl & TextServer::GRAPHEME_IS_RTL) { 
				if (i > 0 && (glyphs[i - 1].flags & TextServer::GRAPHEME_IS_CONNECTED)) {
					cprev_conn = true;
				}
			} else {
				if (glyphs[i].flags & TextServer::GRAPHEME_IS_CONNECTED) {
					cprev_conn = true;
				}