Can't change 'Accept profile submissions from external sites' on Joomla
Joomla 3.8.7 CiviCRM 5.1.1
Administration > System Settings > Misc accepts changes and 'Save' does not show any errors but the new value for 'Accept profile submissions from external sites' is not saved, so reloading the page shows the original unmodified setting.
However, @kcristiano tested on Joomla successfully