Filter applied to clone fields

When a clone flexible content field is used, the format_value function is called causing an issue due to $value being an array versus a string.

php_1    | NOTICE: PHP message: PHP Fatal error:  Uncaught TypeError: strpos(): Argument #1 ($haystack) must be of type string, array given in /var/www/html/wp-includes/shortcodes.php:209
php_1    | Stack trace:
php_1    | #0 /var/www/html/wp-includes/shortcodes.php(209): strpos(Array, '[')
php_1    | #1 /var/www/html/wp-includes/class-wp-embed.php(71): do_shortcode(Array, true)
php_1    | #2 /var/www/html/wp-includes/class-wp-hook.php(303): WP_Embed->run_shortcode(Array)
php_1    | #3 /var/www/html/wp-includes/plugin.php(189): WP_Hook->apply_filters(Array, Array)
php_1    | #4 /var/www/html/wp-content/plugins/advanced-custom-fields-pro/includes/fields/class-acf-field-wysiwyg.php(433): apply_filters('acf_the_content', Array)

Start at includes/fields/class-acf-field-wysiwyg.php around line 433 and trace the filter call into wp-includes/class-wp-embed.php and wp-includes/shortcodes.php around line 209. Reproduce the problem with a clone flexible content field and determine why an array reaches the shortcode processing path. Done means the fatal TypeError no longer occurs for this field configuration.