Iframes inside bootstrap tab disappear when tab is shown

I am currently struggling with strange iframe behaviour: I have bootstrap tab with three youtube iframes in it. When I go to this tab for the first time, iframes dissappear, but if I click on another tab and go back to tab with iframes, they are shown! I've tried forcing iframe reloading with 'shown.bs.tab' event in js, iframes appeared, reloaded but then disappeard. Here is the code inside tab with videos

        div id="videoblog" class="tab-pane fade"
                    ?php 
            $news_query = new WP_Query(array('post_type'='video', 'posts_per_page'=3)); 
            while ($news_query-have_posts()){
                $news_query-the_post();
                $video_link = get_post_meta( get_the_id(), 'youtube_link', true );
                $video_link = str_replace("watch?v=", "embed/", $video_link);
                 ?
                    div class="news-item ?php if($post_num == 0 || $post_num == 2) { echo 'left'; } else { echo 'right'; } ?"
                        div class="videowrapper"
                            iframe src="?php echo $video_link.'?rel=0fs=1'; ?" width="650" height="420" allowfullscreen frameborder="0"/iframe
                        /div
                        div class="news-item-text pt-sans"
                        div class="news-text-wrapper"
                            span class='news-item-date'
                                ?php echo get_the_date('d.m.Y'); ?

                            /span
                            span class="news-item-title"
                                ?php echo get_the_title(); ?
                            /span
                            span class='news-item-excerpt'
                                ?php echo get_the_excerpt(); ?
                            /span
                            /div
                        /div
                    /div
            ?php } ?
    /div

Also I've noticed that if I insert video with 'v/' instead of 'embed/', the videos are shown but fullscreen button doesn't work