DownloadReportToFile skips final chunk

I have a problem where reports are simply terminated too soon.

I am uncertain about the exact cause, but doing a simple division:
file_size / chunk_size = 495.0

I find that my files are suspiciously exactly n * chunk size of (16 * 1024)

The faulty behaviour seems to only happen at the very end of the file, which I guess indicates something about the final chunk of the response byte stream.

If anyone at Google can reference report ids, report number 11035210012 results in the described fault, when using the code below.

This code snippet reliably reproduces the problem for me. Which is functionally identical to the example in this repo:

# Initialize client object.
yaml_path = "~/googleads.yaml"
client = ad_manager.AdManagerClient.LoadFromStorage(yaml_path)

first_date = date(2018, 9, 14)
last_date = date(2018, 9, 14)

# Initialize a DataDownloader.
report_downloader = client.GetDataDownloader(version='v201805')

# Create report job.
report_job = {
    'reportQuery': {
        'dimensions': [
            'DATE',
            'ORDER_ID', 'ORDER_NAME',
            'LINE_ITEM_ID', 'LINE_ITEM_NAME', 'LINE_ITEM_TYPE',
            'AD_UNIT_ID', 'AD_UNIT_NAME',
            'CREATIVE_ID', 'CREATIVE_NAME', 'CREATIVE_SIZE'  # ,
        ],
        'columns': ['TOTAL_LINE_ITEM_LEVEL_IMPRESSIONS',
                    'TOTAL_LINE_ITEM_LEVEL_CLICKS',
                    'TOTAL_LINE_ITEM_LEVEL_CPM_AND_CPC_REVENUE'],
        # 'customFieldIds': ['8918', '12638'],
        'dateRangeType': 'CUSTOM_DATE',
        'startDate': first_date,
        'endDate': last_date,
    }
}

try:
    # Run the report and wait for it to finish.
    report_job_id = report_downloader.WaitForReport(report_job)

except errors.AdManagerReportError as e:
    print('Failed to generate report. Error was: %s' % e)

# Change to your preferred export format.
export_format = 'CSV_DUMP'
report_file = tempfile.NamedTemporaryFile(suffix='.csv', delete=False)

# Download report data.
report_downloader.DownloadReportToFile(report_job_id, export_format, report_file, use_gzip_compression=False)

# Display results.
print('Report job with id "%s" downloaded to:\n%s' % (
    report_job_id, report_file.name))  # report_file.name))

chunk_size = (16 * 1024) # chunk size used for report downloader
file_size = os.path.getsize(report_file.name)
print(file_size / chunk_size) # suspicious integer value