Product variants, prices wrong since update to 4.4.4

Hi,

It's not a problem with the update itself. The problem comes from customization of the product layout on your website. This causes the hidden HTML of the variants to be inside of the product page form instead of being after it.
Because of that, you can see that when you click on the add to cart button, not only the id of the selected variant is sent to the server, but also the id of all the variants of the product:
i.imgur.com/alvVxg5.png
And in such case, the server only sees the last one,f from the hidden variants HTML.
It's likely that you're missing a </div> tag somewhere near the end in the show_default.php view file which leads to the browser into thinking that the hidden HTML of the variants should be inside the form instead of outside.
To confirm this, check the folder templates/YOUR_TEMPLATE/html/com_hikashop/product via FTP.
If you rename that folder, it will deactivate all the view overrides on products and you'll see again the default layout of the product page and the selected variants will be added to the cart instead of the last one.
This will confirm that the issue comes from the customization of one of the view files in that folder.

Regarding the order of the variants, this is dictacted by the setting "Characteristics values ordering" in the HikaShop configuration as well as the "order" that you've entered for each value of the characteristic when you edit the characteristic via the menu Products>Characteristics. So please check these.