Hello friends,
we have update Moodle 2.5 to 2.9.3 version. Before pushing it to user i am running all functionality to check and make default settings. when updating Site News user are not getting notification email. The cron jobs shows email sent but no user is recieving any notification in email. i already checked the subscription. also i am getting this error repeatively while tring to fetch user list subscribed for 'Site News'. for Information we are Using SQL Server. i found the same issue on github but didn't see the solution.

----------------------------------error ----------------
Did you remember to make the first column something unique in your call to get_records? Duplicate value '4571' found in column 'id'.
line 907 of \lib\dml\sqlsrv_native_moodle_database.php: call to debugging()
line 59 of \mod\forum\classes\existing_subscriber_selector.php: call to sqlsrv_native_moodle_database->get_records_sql()
line 69 of \mod\forum\subscribers.php: call to mod_forum_existing_subscriber_selector->find_users()

thanks for your support!!