Bug: Master-Slide does not recognise variable change event anymore

I have a trigger on my master-slide which fires on a variable change event. This event is triggert from a normal slide.

a) This works perfect if I toggle the variable by a storyline action (e.g. a click on button event reults in the action toggle variable). As a result the trigger on the master-slide recognises the variable change and fires.

b) If I toggle the variable by a javascript event, the variable changes in Storyline  but the master-slide does not recognise the variable change. The event "on variable change" does not fire. The Action is not executed. (The result of the variable changes can be also displayed in a textfield on the masterslide)

This bug came with the update from SL2 to SL3. Please fix it. It affects a basic technique of communication between different layers.