Total column value for my table is not automatically updated

Hello.

I am trying to calculate column values from Table

For my numeric label, I am using below expression.

sum({Summary_Report.Table.data},“GRS Lit”)

My table are bind to a few different dataset tag.
So below is my first dataset (lets call it dataset1).

image

And once I replace with dataset2 (without any values inside) for my table, seems like the numeric value still not updated. It still holding the previous value

image

Wondering why it does not show 0 when I already removed the value in Row 1 and 2 ?