Hi again 
found a workaround :
The amazonechocontrol-binding is hindering Alexa to find new Items.
You have to remove amazonechocontrol from addons.cfg … wait until its done
Start searching for new Items in your Alexa App
well done - all items found
afterwards add amazonechocontrol again to addons.cfg
Thats it !
So, the problem is definitely the amazonechocontrol binding here
Regards