### Godot version

3b086aa06

### System information

ArchLinux x11

### Issue description

```gdscript
extends Node

@export_group("My Properties")
@export var number = 3
@export var string = ""

@export_group("Prefixed Properties", "prefix_")
@export var prefix_number = 3
@export var prefix_string = ""

@export_group("", "")
@export var ungrouped_number = 3
```

![image](https://user-images.githubusercontent.com/70787919/214983963-528c415b-745b-47fc-9777-36ebe31a3060.png)


### Steps to reproduce

- create script
- @export_group
- go inspector

### Minimal reproduction project

‮
if (has_expected_type && expected_type.is_hard_type() && expected_type.kind == GDScriptParser::DataType::BUILTIN && expected_type.builtin_type == Variant::NIL) {
			push_error("A void function cannot return a value.", p_return);
		}
		if (has_expected_type && expected_type.is_hard_type() && p_return->return_value->is_constant) {
			update_const_expression_builtin_type(p_return->return_value, expected_type, "return");
		}
		result = p_return->return_value->get_datatype();
	} else {
		
		result.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
		result.kind = GDScriptParser::DataType::BUILTIN;
		result.builtin_type = Variant::NIL;
		result.is_constant = true;
	}
	if (has_expected_type && !expected_type.is_variant()) {
		if (result.is_variant() || !result.is_hard_type()) {
			mark_node_unsafe(p_return);
			if (!is_type_compatible(expected_type, result, true, p_return)) {
				downgrade_node_type_source(p_return);
			}
		} else if (!is_type_compatible(expected_type, result, true, p_return)) {
			mark_node_unsafe(p_return);
			if (!is_type_compatible(result, expected_type)) {
				push_error(vformat(R"(Cannot return value of type "%s" because the function return type is "%s".)", result.to_string(), expected_type.to_string()), p_return);
			}
#ifdef DEBUG_ENABLED
		} else if (expected_type.builtin_type == Variant::INT && result.builtin_type == Variant::FLOAT) {
			parser->push_warning(p_return, GDScriptWarning::NARROWING_CONVERSION);
#endif
		}