Sum Distinct not working in a matrix

Hi v-chenwuz-msft. Thanks for your reply. I'm going to try to explain in plain text first, if it is not enough, I'll have to prepare and share the data you requested.

In JANUARY 2022 I have 406.344 distinct installments ID (real dataset) that where created in JANUARY 2022. Installments come from DEALS. The ROW total in the cohort matrix is correct (= the ROW total is related to installment sum from the distinct DEAL ID):

When I relate PAYMENTS to these INSTALLMENTS, duplicates show up, because deals created will have, along time, installments paid, and more than one payment in many cases (just correcting myself, Installment_ID is DEAL_ID and DEALS have installments, as below):

What I did was a matrix with CREATED_DATE in ROWS (realated to the deals created each month, where each deal has installments) and PAID_DATE in COLUMNS (related to the installments paids each month). Many installments, off course, weren't paid along time. That's why we have 258.109 distinct installments ID created in JANUARY 2022 with no payments:

The problem is when the installments paid are distributed each month, i.e. COLUMNS. I expect to have distinct installments ID paid, with no duplicates. In my cohort we can see that the duplicates still show up. Summing each month, i.e. each column, is more than what is exhibitted in ROW totals. Look at the JANUARY ROW and all months in 2022 (columns): 105.064 (logically, out of 406.344 installments created in JANUARY 22, 105.064 were paid in JANUARY 22) + 79.231 + 67.271 + 49.393 + 42.325 + 34.336 + 4.929 + 380 + 258 + 250 + 265 + 240. Adding it all up we have, in fact, 279.005 (with duplicates) and not what is in the cohort analysis, 148.216 (which is the correct sum, with no duplicates).

The dax formula I used in "values" was:      Sumx(DISTINCT('Table'[ID]),[_Max_Installments])    -> Where ID is the DEAL ID (and DEALS duplicate if more than one installment were paid along time) and Max_Installments are the installments for each deal created.