This is another random Pro issue. I initially set my Graduated Color symbology with the number of classes I want using the method "Manual Interval". I then proceed to change the Upper Values to my desired ranges. As I change these values, sometimes it will just delete a class and go from 5 to 4 classes. In addition, I am unable to change the number of classes as the "Classes" are grayed out. To workaround, I have to go through 'reset' by change symbol type or add a normalization, something to un-gray the classes. Has anyone else experienced this?