Undeletable column in Posts

there is something strange happening on my site. I have in Posts section column called post_views which isn’t created by any plugin and it is also undeletable. I’ve tried searching column name in database and no results found. I’ve also tried disabling plugins and themes one by one and it’s still there.

I’ve also tried unset it with manage_posts_columns hook and it didn’t work.

    add_filter('manage_posts_columns', array($this, 'remove_columns'));		
    function remove_columns($columns) {
    	unset( $columns['post_views'] );
    	return $columns;
    }

Then i tried to var_dump($columns) and found out, that there’s no column called post_views. I’ve also used third party plugin like Admin Columns to get rid off it, but that also doesn’t work. And then I tried to re-install WordPress in hopes of getting restored values and that didn’t work either. I’m out of ideas…

Could someone please tell me where are column values stored and how can I get rid of post_views? Thanks!

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