You are seeing bad data results that do not match the expected record counts of the multiple datasets that you connected to Power BI$.$ What is the first thing to check in the data model?

Start back over and see if you have the same results.

Assume your counts are wrong and that report is correct as is$.$

Merge the files in another program before bringing them back into Power $BI$

Confirm each data set loaded into the model as expected, confirm that auto detect did establish the corrjct relationships.