Pivot Pie Chart Colors All the Same

I create a weekly report and pivot table; to that I added a pie chart and a bar chart. Every day I import new raw data, change the data source and it has worked fine. I have filters set on the pie chart and it has worked. Today when I imported the data, and applied one filter, two adjacent pie slices were the same color; did another filter and the it was fine; another filter and all the pie slices were the same color! why? I have attached examples. And also, why did the square in Legend for one of the items suddenly shrink to a smaller size than the others?