Front end vs Back end values in Demantra Worksheet

In our Demantra, we have following series -

Sales Override - mapped with sales_override ccolumn in sales_Data table

Sales and Operation Planning Forecast - mapped with FCST_CONS1 column in sales_data table

We have client expression to update value in Sales Override series to Sales and Operation Planning Forecast series.

User updates the Sales Override series value to 0

On front end, I can see Sales and Operation Planning Forecast series value updated to 0

However, in back end, i can see that some value (non zero - integer as well as decimals) exist in FCST_CONS1 column (Sales_Override column is updated with 0 value)