Yes it outputs the following in front of the first image/item in the list.
array(0) { }
Let me know the next step you want me to run.
By the way, I have a paid plugin that achieves this desired behavior using shortcodes. You can read about it: https://feastdesignco.com/fsri-shortcode/
But I prefer the GeneratePress framework so I’d like to switch to WP Show Posts if you think we can replicate the same behavior