So you are using the App test versionen v2.0.30? Because the Dimmer Switch Gen. 2 is listed in this version for the first time.
If not, please install this version.
If yes, please post your question in this thread, I guess the chance get help is bigger.
Because I do not have a dimmer switch Gen. 2, I could not try it myself, but @Joka has the same problem, so there must be a bug.
I had only seen in the app test version that the DS Gen. 2 was included.