Sales Invoice item not link anymore?

Helps needed here.
We are using ERPnext for issuing sales invoice. It works fine, all the item can link its price and UOM.

Till today, all the price link is broke, and we cannot add sales item.

I went to customize form for Sale invoice item and tried to change the Rate to Link.
But system will not allow me to. "Fieldtype cannot be changed from Currency to Link in row "

We are very sorry for the problem. We just pushed a fix. Can you refresh and try again?