"Child Class Variables Reset to Default After Compile in Unreal Engine"

“In Unreal Engine, I have a base class MovingPlatform and several child classes. I change the location and moving velocity in a child class and save it. However, when I reopen the project and compile, the values reset to their default (e.g., velocity goes back to 100, which is the default in the base class). Why does this happen, even though all child classes inherit from the same base class?”