I haven’t updated to the latest yet. I’m currently on WooCommerce Version 2.6.14, WC Vendors Version 1.9.8 and WC Vendors Pro Version 1.3.9.
I collected screenshots with captions explaining the issue here: http://imgur.com/a/nBI6R
The items are marked as “In stock”, with 0 in quantity, but with allowed backorder, as the products are made to order.