Copy rows to result behavior

I'm following this guide located at https://www.clearpeaks.com/copy-rows...ult-in-kettle/. I'm using the REST client in one transformation to retrieve a resultset and then using the copy rows to result to pass the resultset to another transformation, where I access the individual fields as parameters. This is mostly working, however I'm finding certain parameters that should have a null value, contain a value for previous field in the resultset. Is this expected behavior? Any ideas on how to overcome this? I'm using pdi 8.2.0.0-342. I have 'Execute every input row' checked.