Your question is Troubleshoot a Data Mapping Issue. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You are working on a data migration or mapping change in a pipeline and the target tables are not matching the source system. Some fields are landing in the wrong columns, derived values are off, and downstream reports are showing inconsistent counts. The issue needs to be isolated quickly so you can correct the mapping and prevent bad data from propagating.
Describe a time you had to troubleshoot a data mapping or data migration issue.