I have created a product-https://www.oownit.com/product/wedevs-test/ and tested with default theme. It was showing variation correctly. There is something wrong with your theme. Please check with a default theme.
If there is plugin issue then you have to update the plugin because in our latest version we do not have any variation issue. Otherwise you have to solve this issue by customizing the plugin. We will release a new fix update within a couple of days.