ACF Recent Posts Query Filter

acf_rwp_query.php

<?php
add_filter( 'acf_rwp_query', 'wp_doin_custom_query' );

/**
 * @hook acf_rwp_query
 */
function wp_doin_custom_query($query) {
	// say we want to limit the query to only single author
	$query['author'] = 1;
	return $query;
}
?>