How did this turn out? I wish it had been public so I could see, because I’ve experienced the same thing with wc_get_template_part()– it renders an empty block, but if you switch to Preview mode and back to Edit, the block renders fine. It works fine on the front end, of course. If I just individually call for the_title, the_content, the_post_thumbnail, for example, it works perfectly on the back end, but I obviously want all the woocommerce goodies like price etc.
It’s been this way for quite a while but it’s not a showstopper since you can toggle preview/edit.