I have just tried with the class you are using and indeed it is not working properly. The change doesn’t work, and the blue one that was already on the scene stays blue. I also tried to create a class based on point light instead of actor, and same thing occurs, it switches to colors assigned on the scene on compile, but only once. I’ve tried to look at the class in visual studio but unfortunately I don’t understand c++.
I can only guess that construction doesn’t work the same for base classes, but I’m not knowledgeable enough