So I think I solved the Mystery
First a Pic of the situation


Like I said nothing happend when player hits the Blue Eventhorizon but now I changed this Entity with a Simple Block
Model and now it works!!!
I don´t know what is wrong with the previous Entity because it worked in the past maybe there is something new in collision detection.So I have to create some more variations of this modell to find one that looks good and works well.
But anyway I want to thank you guys for your time and help.
It´s a great Community!