If a quiz name contains commas, the attempts export (report/overview) fails for csv/xls format with an error ERR_RESPONSE_HEADERS_MULTIPLE_CONTENT_DISPOSITION. Applies only to Chrome browser.

Commas are not escaped properly within the quiz overview report, but it might actually concern the csv export tool.

Test instructions:

• Create a quiz that contains comma in the name
• Submit an attempt
• Visit Quiz report view
• Click 'Download attempts as CSV'
• Get the mentioned error

Dirty fix:
L74 mod/quiz/report/overview/report.php

add str_replace to remove commas:

$table->is_downloading($options->download, str_replace(',', '', $filename),
$courseshortname . ' ' . format_string($quiz->name, true));