SiriKit System default Intents

I added some siri default intents and noticed that they tend to call the system's default apps rather than my app instead.

By adding "in <my app name>" to the end of the invocation phrase it seems to work (at least sometimes. But it still is quite unpredicable and siri often confuses "in <my app name>" with the content of the invocation.

I have two questions that hopefully can be answered by someone more experienced with siri than me:
1) is this "normal" behaviour or are there techniques to improve this? Like setting a default app for handling an intent or such?
2) is it always required to add the "in <my app name>" phrase?
3) will siri get used to it by time? The current performance is not even close to anything I would like to have a customer to deal with :/

Maybe that also has an impact, I'm currently testing in german. When testing in english it feels slightly better.

Thanks for any helful hint / direction!
SiriKit System default Intents
 
 
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