Cross pod data map Step 2: Fetching target data taking a lot of time

Summary: We are trying to send a Proforma scenario data for 18 months from one application to another (BSO to BSO) using cross pod data map but at Step 2: Fetching target data is taking a lot of time

Content (please ensure you mask any confidential information): The same cross pod for Rolling forecast scenario for 18 months is not taking that much time and Proforma is practically copied over from Rolling Forecast so volume of data is the same. Step 2: Fetching target is the step where it is taking maximum time. Does anybody have an idea what could be the root cause for this?