POST without line feed doesn't work, but does the line work?

I am debugging a PHP application where I need to send some data to my server and then parse it and return some values ​​- super simple stuff.

The data is in the format:

action=display_all_pols&donate_form=1&user_state=&state=AK&pols[LA][0][post_id]=2714&pols[LA][0][first_name]=Ralph&pols[LA][0][last_name]=Abraham &pols[LA][0][profile_image]=2762

      

        
        
        
      

    

The size of my data depends on the small size for example. 187 bytes, something larger, for example. 46KB.

I noticed that my application was not parsing POST correctly. The code looks something like this:

function Foo() {
    $state = somehow_get_state();
    $bar = $_POST['pols'][$state];
    // cool logic and stuff

      

        
        
        
      

    

I immediately put it die(var_dump($_POST));

inside Foo()

and noticed that only a portion of the data was actually POSTED.

When I checked this on the command line, I noticed a difference between:

POST http://10.1.10.22/wesupportthat/wp-admin/admin-ajax.php
action=display_all_pols&donate_form=1&user_state=&state=AK&pols[LA][0][post_id]=2714&pols[LA][0][first_name]=Ralph&pols[LA][0][last_name]=Abraham &pols[LA][0][profile_image]=2762

      

        
        
        
      

    

And this (note the row feeds);

POST http://10.1.10.22/wesupportthat/wp-admin/admin-ajax.php
action=display_all_pols&donate_form=1&user_state=&state=AK&
pols[LA][0][post_id]=2714&
pols[LA][0][first_name]=Ralph&
pols[LA][0][last_name]=Abraham&
pols[LA][0][profile_image]=2762

      

        
        
        
      

    

The former will only POST roughly 3.1KB of data, while the later POSTs will do everything.

Is there a reason? I am posting valid JSON and for me love can't figure out why one works and the other doesn't.

To create JSON, I create a nested array like:

array( // root-level array
    array(
        '1' => 'somestring',
        '2' => '...',
        '3' => '...',
        '4' => '...'
    ),
    array( // same as previous),
    // more arrays, potentially up to 50 total
)

      

        
        
        
      

    

and then a call json_encode($my_array, JSON_HEX_APOS);

to create the JSON.

I hope this is just a rubber duck moment. :-)

Edit: I'm walking away from my computer, but the TCP captures are showing the same thing. Also I will add my Apache / php information when I return.