Column Headers Missing

When exporting data using Pages >> Row Evolution >> Export as TSV the column headers now read what appears to be the array position 0, 1, 2, 3, 4, 5, etc. and not the actual column labels. Versions 2.12.0 and 2.12.1

Hi Steve

thanks for reporting this bug. Do you mind creating an issue on Github at: Issues · matomo-org/piwik · GitHub

The issue can be reproduced at this URL on demo: http://demo.piwik.org/index.php?module=API&method=Actions.getPageUrls&format=TSV&idSite=7&period=day&date=2015-04-16,2015-04-22&label=&filter_limit=false&disable_queued_filters=1&format_metrics=1&period=day&expanded=1&translateColumnNames=1&language=en&label=%40%2Findex

Issue #7774