We have recently installed and started to use the Ad-hoc database queries plugin. Today we ran the report "Cohorts by user"; it returned 653 rows. However, when we tried to download the results as a .CSV file Moodle returned a Unknow download file error.

This happens with all contributed reports run via this plugin.

Moodle version: Moodle 3.5.13+ (Build: 20200730)

Hosted OS:  Ubuntu 16.04 Server LTS

PHP version : 7.2.33

MySQL : 5.7.31

plugin version : 3.9 (2020062800)