I am having a problem comparing two fields using Merge Rows (diff) step. My "reference" row is only one field that contains a filename from a result set. The "compare" is a filename from a file directory. I just want to test if the filename from the "reference" row exists in the file directory. If I test this transformation on it's own substituting the result set with a "generate rows" step it works fine. When I run the job I get this error:

2019/05/02 11:16:48 - cdr_file_from_directory.0 - TRIMMED FILE: cdr_StandAloneCluster-1_01_201905021745_3448712019/05/02 11:16:48 - Merge Rows (diff).0 - ERROR (version 7.1.0.0-12, build 1 from 2017-05-16 17.18.02 by buildguy) : Unexpected error
2019/05/02 11:16:48 - Merge Rows (diff).0 - ERROR (version 7.1.0.0-12, build 1 from 2017-05-16 17.18.02 by buildguy) : org.pentaho.di.core.exception.KettleException:
2019/05/02 11:16:48 - Merge Rows (diff).0 - Invalid layout detected in input streams, keys and values to merge have to be of identical structure and be in the same place in the rows
2019/05/02 11:16:48 - Merge Rows (diff).0 -
2019/05/02 11:16:48 - Merge Rows (diff).0 - We detected rows with varying number of fields, this is not allowed in a transformation. The first row contained 4 fields, another one contained 1 : [cdr_file String]
2019/05/02 11:16:48 - Merge Rows (diff).0 -
2019/05/02 11:16:48 - Merge Rows (diff).0 -
2019/05/02 11:16:48 - Merge Rows (diff).0 - at org.pentaho.di.trans.steps.mergerows.MergeRows.processRow(MergeRows.java:99)
2019/05/02 11:16:48 - Merge Rows (diff).0 - at org.pentaho.di.trans.step.RunThread.run(RunThread.java:62)
2019/05/02 11:16:48 - Merge Rows (diff).0 - at java.lang.Thread.run(Thread.java:748)
2019/05/02 11:16:48 - Merge Rows (diff).0 - Caused by: org.pentaho.di.core.exception.KettleRowException:
2019/05/02 11:16:48 - Merge Rows (diff).0 - We detected rows with varying number of fields, this is not allowed in a transformation. The first row contained 4 fields, another one contained 1 : [cdr_file String]
2019/05/02 11:16:48 - Merge Rows (diff).0 -
2019/05/02 11:16:48 - Merge Rows (diff).0 - at org.pentaho.di.trans.step.BaseStep.safeModeChecking(BaseStep.java:2121)
2019/05/02 11:16:48 - Merge Rows (diff).0 - at org.pentaho.di.trans.steps.mergerows.MergeRows.checkInputLayoutValid(MergeRows.java:262)
2019/05/02 11:16:48 - Merge Rows (diff).0 - at org.pentaho.di.trans.steps.mergerows.MergeRows.processRow(MergeRows.java:97)
2019/05/02 11:16:48 - Merge Rows (diff).0 - ... 2 more
2019/05/02 11:16:48 - Merge Rows (diff).0 - Finished processing (I=0, O=0, R=2, W=0, U=0, E=1)
2019/05/02 11:16:48 - see_if_file_received_from_sftp - Transformation detected one or more steps with errors.
2019/05/02 11:16:48 - see_if_file_received_from_sftp - Transformation is killing the other steps!
2019/05/02 11:16:48 - see_if_file_received_from_sftp - ERROR (version 7.1.0.0-12, build 1 from 2017-05-16 17.18.02 by buildguy) : Errors detected!
2019/05/02 11:16:48 - select_only_one_field_from_file_directory.0 - Finished processing (I=0, O=0, R=1, W=1, U=0, E=0)
2019/05/02 11:16:48 - cdr_file_from_directory.0 - Finished processing (I=0, O=0, R=1, W=1, U=0, E=0)
2019/05/02 11:16:49 - see_if_file_received_from_sftp - ERROR (version 7.1.0.0-12, build 1 from 2017-05-16 17.18.02 by buildguy) : Errors detected!
This makes no sense as you can see there is only one field coming in from either side. How could there be 4? Also I thought I could attach a transformation here....

I have attached the transformation.