Hi Silverpit
The colors of those profile circles are generated randomly using an algorithm, why that changed is a mystery, though I do know we as users ave no control over the color of those profile circles
Don't worry, that changing color is not indicative of anything being wrong or anything like that
Here is a discussion on the color of those profile circles, which was answered by Microsoft Staff:
https://answers.microsoft.com/en-us/msoffice/fo...