Wrong Grand Total of Blended Table

I migrated recently to Looker studio from Power Bi and my client has been loving the experience.

Recently I we wanted Grand total on our chart, see attached. Notice that only a select data entry is showing as grand total value and not the aggregated sum as per the particular view.

I have checked online and have not seen a solution to this, thanks in anticipation.

Anthony

Without more information on how are you blending the two tables, my guess here is that the aggregate function is MIN instead of SUM.