Bug- Query display with array

Hi,
I am trying to show the query result for a combination of taxonomies:
Category= nature and video-type (my custom taxonomy) = lecture. The posts should be displayed only if both the conditions are satisfied.

Here is the code I am using:

<?php
				$article_count=0;
				$args = array(
								'video-type' => 'lecture',
								'category' => 'nature',
							);
				$query = new WP_Query( $args );
				$article_count = $query->post_count;
				if ($article_count) {
						echo "

<ol>";
							$posts = $query->posts;
							foreach ($posts as $post) {
									echo "

<li> <a>".$post->post_title."</a> </li>
";
									}
								echo "</ol>
";
							}
					?>

[Please use the code button, NOT blockquote when posting code]

The code is somehow displaying all the values that are valid for taxonomy condition video-type = lectures irrespective of category value.
However, for custom taxonomies (checked another one), it seems the condition is working. Can you please let me know if there is some issue or I am doing something wrong?
Also, the list numbering

is not apprearing
Thanks!