the_date doesn't show in one of posts

Hello,
I was using a custom template using the following code

<div class="dpe-flexible-posts">
	<?php while( $flexible_posts->have_posts() ) : $flexible_posts->the_post(); global $post; ?>
		<article>
		<?php if( $thumbnail == true ) {
		if( has_post_thumbnail() ) { ?>
		<?php the_post_thumbnail( $thumbsize ); ?>
                <?php } elseif( 'image/' == substr( $post->post_mime_type, 0, 6 ) ) {
		echo wp_get_attachment_image( $post->ID, $thumbsize );
	   }  }	?>
		<a href="<?php the_permalink(); ?>"><?php the_title(); ?</a>
		<?php the_date('d F Y'); ?>
                <?php the_excerpt(); ?>
		</article>
	<?php endwhile; ?>
	</div>

It is working alright, but the problem with the_date, there is always a post that is not showing it. There’s no pattern for it, if only one post it will have the_date but if more than one the_date will be missing in one of the posts. Any idea what may cause this issue?

https://www.ads-software.com/plugins/flexible-posts-widget/