No, I mean to retrieve posts that have “tag a” AND “tag b” rather than “tag a” OR “tag b” using the AV blog post shortcode.
( [av_blog blog_type='taxonomy' categories='678' link='post_tag,748,95' blog_style='blog-grid' columns='3' contents='excerpt' content_length='content' preview_mode='auto' image_size='portfolio' items='3' offset='0' paginate='yes'] )