After a battle two of my Champions leveled up, the faction leading Champion and another one.
For the faction leader the light blue circles around the previously selected traits were correct.
For the other Champion the light blue circles were the circles for the faction leading Champion, giving a wrong hint on what is available.
The selection of traits for leveling up was possible as required for the second Champion therefore I was able to select the upgrades I wanted in the end, but the colorcodes meant to help were wrong. (In explicit, there was a light blue circle around Experience +15%, although the Champion did not have the trait. I was able to select it (changing it into golden circle) and when deselecting it the light blue circle did not return. Selecting it again and pressing ok worked fine.)
It seems to be only the initial setting for starting the window for the second Champion being leveled which is buggy?!