Function only running once per import

I’ve created a function that long story short extracts a zip file, adds the images to the media library and returns a list of the image URLs to a WP all import ACF gallery field, and it works perfectly, the problem is it only works perfectly for one of the imported items – it seems to run once and not again. Am I missing something? I can’t see anything in the documentation about it.

Function code is:

function extract_images_from_zip_and_upload($zip_file_url) {
    // Download the zip file
    $zip_file_contents = file_get_contents($zip_file_url);
    // Create a temporary file to store the contents
    $temp_file = tempnam(sys_get_temp_dir(), 'zip');
    // Write the contents to the temporary file
    file_put_contents($temp_file, $zip_file_contents);

    // Extract the zip file
    $zip = new ZipArchive;
    $zip->open($temp_file);
    $zip->extractTo(get_temp_dir());
    $zip->close();

    // Get all the image files from the extracted folder
    $images = glob(get_temp_dir() . '/*.{jpg,jpeg,png,gif}', GLOB_BRACE);

    // Array to store URLs of the uploaded images
    $image_urls = array();

    // Loop through the image files and add them to the media library
    foreach ($images as $image) {
        $file_array = array(
            'name' => basename($image),
            'tmp_name' => $image
        );

        $attachment_id = media_handle_sideload($file_array, 0);
        if (is_wp_error($attachment_id)) {
            continue;
        }

        $image_url = wp_get_attachment_url($attachment_id);
        $image_urls[] = $image_url;
    }

    // Clean up
    array_map('unlink', glob(get_temp_dir() . '/*'));
    unlink($temp_file);
    //Return the URLs of the uploaded images separated by commas
    return implode(",", $image_urls);
}