Yellow background in widget

Hi all, 

Has anyone seen this before? Not something I've spotted before and can't work out what caused it to occur!

I made a new pivot table widget and one of the columns is appearing with a yellow background (screenshot below). It only shows in yellow when viewing the dashboard (not when you go into the widget). 

Probably a random bug, but could be a really good feature to know about if you can change backgrounds for these! I just can't work out how I possibly did it within a pivot table! Seems to be holding it's colour even after logging in/out of Tessitura and when duplicating it. I'm using the same criteria in other widgets, but they still appear white. 

Thanks,

Alison