Fix a potential encoding issue in diag_system_activity.php. Fixes #8300
(cherry picked from commit c083e1e49af4902d15173d412feebd8b86a616ee)
Fix a potential encoding issue in diag_system_activity.php. Fixes #8300
(cherry picked from commit c083e1e49af4902d15173d412feebd8b86a616ee)