Attempting to insert options into a content block, but only if that content block was selected.

acf-content-blocks.php

<?php 
/**
*  Load default choices from options page into content blocks
*/
function acf_load_style_default_choices( $field ) {
    
    // reset choices
    $field['choices'] = array();


    // if has rows
    if( have_rows('additional_styles', 'option') ) {
        
        // while has rows
        while( have_rows('additional_styles', 'option') ) {
            
            // instantiate row
            the_row();
            
	    // vars
            $value = get_sub_field('value');
            $label = get_sub_field('label');

            // get the options chosen from the checkboxes
            $cb_options = get_sub_field('associated_content_blocks');

            // get the current content block
            $cb = get_row_layout();

            // replace the spaces with underscores, make lowecase
            $cb_formatted = strtolower(str_replace(' ', '_', $cb));

            // check to see if the current content block is within the cb_options array
            if ( in_array($cb_formatted, $cb_options) ) {
            
	            // add to options for that content block
	            $field['choices'][ $value ] = $label;

	          }
            
        } 
        
    } 

    // return the field
    return $field;
    
}