I was checking the server logs and noticed two PHP errors being caused on every page view by Ad Agency Pro.
[08-Feb-2016 02:24:35 UTC] PHP Warning: Illegal string offset 'campaign_id' in /home/[sitedomain]/public_html/components/com_adagency/ijoomla_ad_agency_zone.php on line 449
[08-Feb-2016 02:24:35 UTC] PHP Warning: Illegal string offset 'campaign_id' in /home/[sitedomain]/public_html/components/com_adagency/ijoomla_ad_agency_zone.php on line 465
If you will investigate this issue, it will be appreciated.