Publishing issue with Product Variants
It looks like the user interface for editing product variants has changed recently (?).
Instead of opening a detail panel for the product variant, they are all located on the same level as the product and edited inline.
We just encountered an issue where we added a product variant, but it wasn't showing up on the site. To get the Product Variant to show on the site we had to make a small change on the Product and then save&publish that.