using method from indirect parent

Consider following code:

class user_error : public std::runtime_error
{
public:
    using std::exception::what;
    explicit user_error(const std::string& what_arg):std::runtime_error(what_arg){}
};


class with_overriden_what : public user_error {
public:
  with_overriden_what(const std::string& val) : user_error("user_error"), message(val) { }

  std::string message;

  virtual const char* what() const noexcept {
    return message.c_str();
  }
};

with this calls:

with_overriden_what ex("thrown");
std::cout << "1. direct result: " << ex.what() << "\n";
std::cout << "2. sliced result: " << static_cast<user_error>(ex).what() << "\n";
std::cout << "3. ranged result: " << ex.user_error::what() << "\n";

It is surprise for me that result of 2 and 3 is different:

1. direct result: thrown
2. sliced result: user_error
3. ranged result: std::exception

Q: Is there a paragraph in standard that address this behaviour?