C# Strangeness

public void Test()
{
        string aa = "\0";
        string cc = "";

        var r0 = aa == cc;
        var r1 = aa.Equals(cc);
        var r2 = cc.Equals(aa);
        var r3 = aa.CompareTo(cc);
        var r4 = cc.CompareTo(aa);
}

Thanks to FsCheck for pinpointing this "feature".