### Godot version

4.1.0

### System information

Windows 10, i711800H, Forward+ Vulkan

### Issue description

When using @export_group("Name") in a BaseClass, then inheriting from that BaseClass in another class and there also using @export_group("Name"), with the same group name, then running the project and re-saving the inherited class the project crashes with 
```
ERROR: FATAL: Index p_index = 3 is out of bounds (size() = 3).
   at: get (./core/templates/cowdata.h:155)
```

sometimes the editor crashes too after a while.

### Steps to reproduce

1. open reproduction project
2. Run the project.
3. Open the "super"script
4. Press CTRL + S to save it.

### Minimal reproduction project

[MRP_.zip](https://github.com/godotengine/godot/files/12137412/MRP_.zip)

if (operand.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
				gen->pop_temporary();
			}
			return result;
		} break;
		case GDScriptParser::Node::ASSIGNMENT: {
			const GDScriptParser::AssignmentNode *assignment = static_cast<const GDScriptParser::AssignmentNode *>(p_expression);
			if (assignment->assignee->type == GDScriptParser::Node::SUBSCRIPT) {
				
				const GDScriptParser::SubscriptNode *subscript = static_cast<GDScriptParser::SubscriptNode *>(assignment->assignee);
#ifdef DEBUG_ENABLED
				if (subscript->is_attribute && subscript->base->type == GDScriptParser::Node::SELF && codegen.script) {
					HashMap<StringName, GDScript::MemberInfo>::Iterator MI = codegen.script->member_indices.find(subscript->attribute->name);
					if (MI && MI->value.setter == codegen.function_name) {
						String n = subscript->attribute->name;
						_set_error("Must use '" + n + "' instead of 'self." + n + "' in setter.", subscript);
						r_error = ERR_COMPILATION_FAILED;
						return GDScriptCodeGenerator::Address();
					}
				}
#endif
				
				StringName assign_class_member_property;
				GDScriptCodeGenerator::Address target_member_property;
				bool is_member_property = false;
				bool member_property_has_setter = false;
				bool member_property_is_in_setter = false;
				bool is_static = false;
				GDScriptCodeGenerator::Address static_var_class;
				int static_var_index = 0;