Pivot Cell Styling inconsistent

I am having trouble getting the styling on table cells consistent on pivot tables.

I am trying to get the line in the attached image between the 3rd and 4th columns all the way down but the styling seems to only apply to the last cell in a sub section. What is different between the last cell in the subsection and the cells preceding it that causes this? Is there an additional selector I need to use?

I am using the following script

 

 

 

 

 

widget.transformPivot(
  {},
  function (metadata, cell) {
       //set default side and tob/bottom cell colors
    	cell.style.borderColor = 'lightgrey transparent';
      //set line to separate columns 3 & 4
	   if (metadata.colIndex == 2) {
      cell.style.borderColor = 'lightgrey lightgray lightgrey transparent'
    }
	   if (metadata.colIndex == 3) {
      cell.style.borderColor = 'lightgrey transparent lightgrey black'
    }
	
  }
);
//Set the default border color as transparent for the table cells
prism.on("dashboardloaded",function(){
	
	const style = document.createElement("style");
        const node = document.createTextNode(`.table-grid__cell{border-color:transparent ;}`);
         style.appendChild(node);
	document.head.appendChild(style)
})