Invalid timezone

My site health was reporting a critical error with an invalid timezone: PHP default timezone was changed after WordPress loading by a date_default_timezone_set() function call. This interferes with correct calculations of dates and times. The cause was traced back to the Countdown Timer plugin. Commenting out lines 147–150 of fergcorp_countdownTimer.php fixed the issue: $tz = get_option('timezone_string'); if ( $tz ){ //Get and check if we have a valid time zone... date_default_timezone_set($tz); //...if so, use it } This was in a PHP 8.3 environment.