Course Completion was working fine before we upgraded to 2.3.1 from 2.2. However, after the upgrade we can no longer mark anything completed on Course Completion Report. When we try to mark an activity completed we get the following error:

Fatal error: Cannot use object of type stdClass as array in /Moodle/lib/completion/completion_criteria.php on line 170

The error is occurring on /course/togglecompletion.php according to the url on the browser.