Custom BS not working through Asynchronous call

Hi All,  We are facing issue while loading an CSV file attachment data of an activity by modifying the data runtime using below approach/configuration.

1. Initiate a custom workflow call on custom button click.

2. Server Request business service call to call another custom workflow asynchronously through invoking workflow process batch manager component in Direct DB mode.

3. A custom business service is used to read and load the attachment file as part of custom workflow used in above step 2

We have modified the custom BS code to clean the special characters from attached file and load into custom table which is shown under another view of Activity screen.  Issue: We are not able to see the cleaned data after the execution of above steps through button click. It is loading the actual data available in file. But we can see the same custom BS is working and loading the cleaned data if we execute it through business service simulator. Can anyone please confirm why the same BS is not working when it is executed through Asynchronous workflow call?