This is the same bug as http://issues.liferay.com/browse/LEP-1027, which is an old bug but apparaently still not fixed.
Steps to reproduce:
- Add Shopping portlet to a page
- Add a category
- Under category, add a new Item
- Set a price for the item (40.00 for example) and click to Add price, then Save the Item
- Change language to Dutch (or any language in which number formats include a comma and not a dot)
- Go back to edit the previously created Item
- Note that the price is displayed as 40,00 (with a comma instead of a dot)
- Click to add price
Expected result: A new set of fields for a new item should simply appear.
Actual result: The price of the previously created item is reset to zero.