During 1.20wmf6 upgrade, a good number of instances of these errors where observed in the logs:
Jun 27 18:43:28 10.0.8.26 apache2[1589]: PHP Notice: AggregateMessageGroup::exists[agg-WMF_Blog_Posts]: Group is empty in /usr/local/apache/common-local/php-1.20wmf6/extensions/Translate/Groups.php on line 649
Jun 27 18:43:32 10.0.8.26 apache2[1589]: PHP Fatal error: Call to a member function getWorkflowConfiguration() on a non-object in /usr/local/apache/common-local/php-1.20wmf6/extensions/Translate/specials/SpecialLanguageStats.php on line 281
Version: master
Severity: trivial