Currently (Pro 3.0.3) when you add classes to graduated color symbology and are using one of the default classed color schemes, the number of colors in the scheme does not update. For example, if you configure your symbology using 4 classes and bump it up to 8...
...you end up with four pairs of symbol classes that have the same color. Not good. The point of symbol classes is to provide differentiation, so it would make more sense if the ramp updated to the 8-color version when 8 classes are selected. Right now that requires another click, scroll, click. This becomes extremely annoying when you're trying out different options and have to manually do this for every single edit.
Expected outcome: