RANKX trun 1 after insert extra column

Hi

I am new in PowerBi  and I learn  a lot in the Community Blog

the Rankx work fine if I just put the ItemID , Sum of Qty and Rank using Table visual

Sum of QTY = SUM('PWBI'[QTY]) and rank = RANKX(ALL(PWBI[ItemNumNoZ]),[Sum of QTY],,DESC,Dense)

If I insert a  extra coloumn , it will show all the item and rank will change 1.

What I need to change  the measure?

thank-you