Related posts gallery display weird

Hi!
Once again, thank you for this wonderful theme!

I’m applying a related posts by taxonomy plugin’s shortcode on the post content area and the results don’t display in accordance to the shortcode [related_posts_by_tax format="thumbnails" image_size="medium" posts_per_page="2" columns="2" title="Quero Mais!" before_title='<h3>' after_title="</h3>"]
The thumbnails are aligned but half-way on top of each others and no titles.
When I add
add_filter( 'use_default_gallery_style', '__return_false' );
to the functions.php of my child-theme and the CSS styling to the style.css also, it stacks the thumbnails in 1 column on the left without substituting the gallery_style.

I love the responsive style of dimming the other thumbnails when we hover over one of them, though; but I need it in columns and with titles below. What could be the conflict? Can you help?

I was experimenting with Virality theme before I found Careta and it was working there, until I made the theme change. I really like Careta :p Please throw some light to me.

I’m in my localhost, so, only screenshots available.