Duplicate EAN

On UI I am able to create multiple items with same EAN. Although it gives error when saving but somehow the item is created.

The result is now we have multiple items with same EAN and when we try to update the quantity or price or cost of the item having duplicate EANs via API we get Error

{

    "httpCode": "422",

    "httpMessage": "Unprocessable Entity",

    "message": "Item not updated. Item with matching ean already exists. ItemID: 45, ean: 1870167970039, desc: Assembly Items",

    "errorClass": "Exception"

}

.

So how can we update in this scenario?