Post Links are not working on under 768px - php

Question

The website is http://www.mercuriusresearch.co.uk which runs on Wordpress and based on Bootstrap.
The error shows when you resize the screen below 768px, all the post title links stop working. The actual HTML is still showing the href but the post titles just behave like normal text.
The error is displaying across the website (i.e. on all post title links) but only on those sections of the page that are taking links from Wordpress. For example, the sidebar links on my homepage work on all screen sizes.
I haven't had this problem before. My suspicion, based on the previous paragraph, is that it relates to Wordpress somehow...but I am using the same code that I always use to bring in the titles from Wordpress. So that, and the fact that the error appears to relate to the size of the screen, leads me to think that Bootstrap is somehow related too.
Any help would be much appreciated.
The only code that isn't on the website is this, which is the Wordpress loop:
<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
<div class="post-date">
<?php k99_relative_time(); ?>
</div>
<div class="post-title">
<?php the_title( sprintf( '<h3 class="entry-title">', esc_url( get_permalink() ) ), '</h3>' ); ?>
</div>
<div class="post-excerpt">
<?php the_excerpt(); ?>
</div>
<div class="read-more">
Read more →
</div>
</article>
As I say though, this is working on larger screen sizes and if there was something wrong with this section, it obviously would occur on all screen sizes. All the other code is there on the website (obviously, I am not sure what part exactly is relevant, or I wouldn't I have this problem).

Answer 1

For a quick solution, you can write CSS using media query for devices below 768px and your links will work fine.
#latest-news-front,
#stock-ideas-front {
position: relative;
z-index: 10;
}

Answer 2

There is a div that covers all of the other divs you use.
If you look in your element inspector you can see the div.
You can float the sidebar-front div, but there is a change that other divs will behave different.
aside#sidebar-front {
float: left;
}
or clear every div by using the following code at the end of each one.
clear: both;