I was working on woocommerce for a project, and was looking for the same zoom in function. Came across this plug, it’s not this plug bug. It’s built in woocommerce by default like that. To enable the featured image as in thumbnail gallery, go to plugins/woocommerce/templates/single-product dir and comment out this line:
‘post__not_in’ => array( get_post_thumbnail_id() ),
//’post__not_in’ => array( get_post_thumbnail_id() ),
Now you should be good, all the images should be there in thumbnail gallery for a product including the featured image.
Hope, it works for you guys.