Boarders generate below pivot table after changes

[stealthbob]

I have a simple pivot table and prefer no gridlines, this will be used for simple reporting.

At issue is when I utilize a slicer and select a button that displays less lines than the one before it adds borders to the area that was previously populated. I can manually go into Format>Borders>Select None and it goes away.

How can I stop the boarders from being generated in the first place?

Many thanks