lovata-shopaholic wintercms not saving the preview_image while create product

in lovata-shopaholic plugin when i go to create product and add preview image in the page it saved the image and show in the page.

  • when i save the product with submit it will redirect to the update page with latest ID.
  • but when i check the preview image on update page there is nothing.
  • if i update the image from update product page it works!

I have tried to check it with new added field but still its not working with new field too.