Trouble with a Filtered Query Loop

I’m having some trouble I can’t figure out. I created a query loop that filters content based on the presence of a custom field. It’s also set to only show 3 posts. However, sometimes it works perfectly (shows 3 posts, images all formatted properly), but then other times it only shows 2, and then other times it doesn’t format the photo properly. The inconsistency of the behavior is confusing me.

Based on other threads in the support area, I am filtering the records by creating a custom snippet (pasted below) and assigning a class to the grid block of the query loop.

add_filter( 'generateblocks_query_loop_args', function( $query_args, $attributes ) {

    if ( ! empty( $attributes['className'] ) && strpos( $attributes['className'], 'am-to-sell' ) !== false ) {

        $meta_query = array(
            array(
                'key' => 'inventory_status',
                'value' => 'For Sale', // 0 is 'To Sell' and 2 is 'Sold'
                'compare' => '=', // Use '=' for true, '!=' for false
            ),
        );

        $query_args = array_merge( $query_args, array(
            'meta_query' => $meta_query,
        ) );
    }

    return $query_args;
}, 10, 2 );

Screenshots: https://postimg.cc/gallery/xd6wZ78

Thanks for any assistance you might be able to offer.

— Aaron