excluding current post from get_posts

i have this block of code displayed in single.php template

<ul class="cat-wrap">
    <?php 
        global $post;
        $categories = get_the_category();
        foreach ($categories as $category) :
    ?>
    <h5>same from <?php echo $category->name; ?></h5>
    <?php
        $args = array(
            'numberposts' => 5,
            'category' => $category->term_id,
            'post__not_in' => array( $post->ID )
            );
        $posts = get_posts($args);
        foreach($posts as $post) :
    ?>
    <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
    <?php endforeach; ?>
   <li><a href="<?php echo get_category_link($category->term_id);?>" title="View all posts filed under <?php echo $category->name; ?>">جميع مقالات قسم <?php echo $category->name; ?></a></li>
    <?php endforeach; ?>
  </ul>

the loop is working fine except 'post__not_in' => array( $post->ID ) behaving in a weird way . to explain more if i have a post that share 4 different categories . the generated code is the following

<ul>
<h5>same from Cat1</h5>
<li>another article 1</li>
<li>another article 2</li>
<li>another article 3</li>
<li>another article 4</li>

<h5>same from Cat2</h5>
<li>Current Article</li>
<li>another article 1</li>
<li>another article 2</li>
<li>another article 3</li>

<h5>same from Cat3</h5>
<li>Current Article</li>
<li>another article 1</li>
<li>another article 2</li>
<li>another article 3</li>

<h5>same from Cat4</h5>
<li>Current Article</li>
<li>another article 1</li>
<li>another article 2</li>
<li>another article 3</li>

like you can notice only <h5>same from Cat1</h5> that excluding the current post , the rest including it and excluding some other random post.

thanks in advance and i hope i managed to explained my problem.