When I visit the Ban List I get the following Warning at the Top of my Screen:

Clicking the Enable here button takes me to the ticket filters section:

Adding an email despite this produces the following error:

Emails still are added to Ban List despite this:

FYI Trying to enter a duplicate entry produces the following error:
[INSERT INTO Support_filter_rule
SET isactive
= '1', what
= 'email', how
= 'equal', val
= 'REDACTED EMAIL ADDRESS', updated
= NOW()]
Duplicate entry '0-email-equal-REDACTED EMAIL ADDRESS' for key 'filter'<br /> <br />
---- Backtrace ----<br />
#0 (root)/include/mysqli.php(199): osTicket->logDBError('DB Error #1062', '[INSERT INTO S...')<br />
#1 (root)/include/class.orm.php(3454): db_query('INSERT INTO
Su...', true, true)<br />
#2 (root)/include/class.orm.php(658): MySqlExecutor->execute()<br />
#3 (root)/include/class.filter.php(667): VerySimpleModel->save(true)<br />
#4 (root)/include/class.filter.php(187): FilterRule->save()<br />
#5 (root)/scp/banlist.php(61): Filter->addRule('email', 'equal', 'REDACTED EMAIL ADDRESS', Array)<br />
#6 {main}
REDACTED URL
Here is my system details:

Additionally all banned emails were not copied across during the upgrade from 1.10.4 -> 1.11 stable.
Any help would be much appreciated.