Can't save category order

-- HikaShop version -- : 2.5.0
-- Joomla version -- : 3.4.3

I tried to set my category order (adding new category or dragging existing categories), but saving the product, the categories still have the last order i saved. As in the picture, I add two new categories, and then I would move "kartell" category at the end of the list, but nothing. It keeps the third position.
I also noted that the categories tree is not correctly updated if I add new categories and i save a new order.
What could be the problem?

Thank you so much.