This worked for me! (very random)

I was comparing the database entries of the new gallery (which works and displays correctly) to an older gallery which was not displaying within the image store or within the embed code in a blog post.

This may not matter, but I changed the path to the image (i removed the /_resized/ directory seeing as the new galleries do not point to it) but i think the simple act of editing the wp_posts table entry and clicking save somehow knocked sense into it.

Now my galleries display within the image store, and i simply removed the old embed code from my blog post and embedded again with the new embed feature and now that is visible as well.

Give it a shot, let me know if it’s just me.