When HFP mode is used for voice navigation, then the statement is cut, because the connection to the channel takes longer as in A2DP mode. There is an individual voice delay in seconds (1,2,3,4,5,6) needed, depending on the connected device to delay speech via HFP mode.
Thanks for the suggestion!
We are aware of that and I have already added a delay in “Phone call audio” to allow the connection to complete before the voice guidance is activated.
Currently it’s under testing for next Kurviger version. 
Adding an option for the delay value could be useful too.
Do you find that such large value as 6" exists in some devices?
6 sec. is maybe not necessary… 2-3 should be sufficient… only in my car… an old renault navigation system… this is awfully slow… it may take up to 6, but up to 2-3 should be ok.
Just to provide an update in this thread as well. This function has been implemented. For more details see the release notes: Kurviger 1.1.19