It appears that other applications installed on the phone tries to integrate to android too.
They do that a way that doesn't allow clever features like the one provided by us such as Filtering/Rewriting rules.
You have two choice :
Continue using our integration and install plugins to support other applications. (This will allow to apply filtering/rewriting rules on these applications too).
To do so, choose to always use mobile dialer instead of other applications using the checkbox when you'll make your next call.