How to populate multiple columns in a grid?

Hello everyone, 

I have put together a script that clicks on a rich text link to add a row to a grid and write data into the columns. The first column is a picker field. The second column is a simple text field, but FitNesse is failing to write the data into this field. 

Has anyone else experienced anything similar to this? 

Things to know,

I'm running the latest FitNesse for Appian version: 18.4.1

Our application is still running Appian version: 18.2

My code for writing the data to the grid is as follows:

!*** Add New Recipient Point of Contact row and Enter Recipient Username and Title
!| script |
|click on link|Add A New POC |
|populate grid|[1]|column|[1]|row|[1]|with value|Username|
|populate grid|[1]|column|[2]|row|[1]|with value|Title|
***!

The error message that I receive is as follows:

Invalid argument: Populate Field - - Y

Thank you!