why data breaking when applying filters on Dim to Dim

Hi,

I have a data set where i want to find out current date of count and  Previous end date of the moth count . dashboard is showing Current and and historical Data in a one filter.

I am tying yo achieve this using full outer join, i am getting current date count in a CTE then doing the full join i am getting Previous end date of the moth counts. now am segregate this count base on product and division. When i segregate data base on the product Previous end date of the moth counts are not changing. when When i segregate data base on the on the division the Previous end date of the moth counts are changing. product is coming from fact table and division is coming from Dimension table. can any one tell me why it's breaking when applying filters on Dim to Dim.