Result of CityHash64 doesn't match the reference implementation on strings of 64*n (n > 1) lengths

[ghost]

using System.Collections.Generic;
using System.Data.HashFunction.CityHash;
using System;
using System.Text;

namespace HashTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var symbols = new List<char>{'a', 'b', 'x', 'y'};
            var hasher = CityHashFactory.Instance.Create(new CityHashConfig{ HashSizeInBits = 64 });

            foreach (var symbol in symbols)
            {
                for (var length = 2; length < 4; ++length)
                {
                    var s = new string(symbol, length*64);
                    var bytes = Encoding.ASCII.GetBytes(s);
                    var hash = BitConverter.ToUInt64(hasher.ComputeHash(bytes).Hash, 0);
                    Console.WriteLine($"{symbol}, {length}: 0x{hash:x}");
                }
            }

            Console.ReadKey();
        }
    }
}

vs python (uses reference implementation, via cityhash module)

import cityhash

for symbol in ('a', 'b', 'x', 'y'):
    for length in (2, 3):
        hash = cityhash.CityHash64(symbol*length*64)
        print("{}, {}: {:#x}".format(symbol, length, hash))

vs C++ (using https://github.com/google/cityhash via conan)

#include <string>
#include <cstdio>

#include "city.h"

int main(int, char*[]) {
	for (const auto symbol : {'a', 'b', 'x', 'y'}) {
		for (const auto length : {2, 3}) {
			const auto s = std::string(length*64, symbol);
			const auto hash = CityHash64(s.data(), s.size());
			printf("%c, %d: 0x%lx\n", symbol, length, hash);
		}
	}

	return 0;
}

C#:

a, 2: 0x17eb9429608efa10
a, 3: 0xd173291f9db2d8d1
b, 2: 0xd7f220816e41070d
b, 3: 0x36074be8fc81c410
x, 2: 0x77f3f0a5f76761d5
x, 3: 0xfe9c5c96274e4df9
y, 2: 0x85b294ba426c41c7
y, 3: 0xd7dcefe6faea4424

Python and C++:

a, 2: 0x8732752111926e2c
a, 3: 0xf7b22b0a38b54ca8
b, 2: 0x9f0c541d796fd1f1
b, 3: 0x453fb3d655153452
x, 2: 0x87e1532e643b0d29
x, 3: 0x128cf8134a32840
y, 2: 0xdf18ce2fbf974758
y, 3: 0x28e79fea5420f5f5

It looks like there is a difference in tail symbol processing