500 error from call to XMLHttpRequest()

I am getting a 500 error on the Linux version of my code. The version on my WAMP under windows doesn't have this issue. The LAMP version is a Bitnami  instance running on AWS. I took a look in the error.log and I see:

malformed header from script 'index.php': Bad header: {"0":["{choose}","IOS","Mac","
and 
AH01070: Error parsing script headers

I see that AH01070 is an Apache bug. I am running on AWS LightSail. 

 This is where I set my headers in my CI code:

$this->output
   ->set_content_type('application/json')
   ->set_header("Access-Control-Allow-Origin", "*")
   ->set_output(json_encode($table));

Any ideas? Do I need to move back to Windows?

proof that an old dog can learn new tricks