In the 2.1.4 version we introduced a bug that caused the prices of variations to be hidden when the manage stock field was left empty. Sorry about that. This and a couple other small bug fixes are now available in the WooCommerce 2.1.5 release, available via WordPress.org or automatic update in your administration panel.
Just 14 commits in total went in this release, which makes it a really small fix release, but as it solves a big bug we decided to push it out immediately. All the changes can be found in the changelog.
(As always, the comments on this post are closed because this is not the right platform for support requests.)