Export to excel using exportPopupComponent not exporting table data

Windows 7
Pentaho 5.0.7
Ctools Installed Version: v14.05.06
Hiya,

My "export to excel" button using the exportPopupComponenent does not export table data when one of my 3 input components is blank.

I have 3 input components, two date inputs and a multi select. I have made either of the two date inputs optional. All is good when all 3 inputs are selected and populated, the resultant dataset can be exported successfully with the "export" button. If however, one of the date inputs are left blank the returned dataset is not exported when the button is pressed, the file is empty.

I can see in the webconsole a call to the cda file when I press the export button, so my assumption is that the blank parameter is causing the issue. Is there anyway around this?
The catalina and pentaho log files did not give anything helpful.

Ta,