FacetWP – force get_the_post_thumbnail() to include a title tag

<?php

// Add to your (child) theme's functions.php

add_filter( 'wp_get_attachment_image_attributes', function( $attr, $attachment ) {
    if ( ! isset( $attr['title'] ) ) {
        $title = get_the_title( $attachment->ID );

        if ( ! empty( $title ) ) {
            $attr['title'] = $title;
        }
    }

    return $attr;
}, 10, 2 );