If it's the front speakers, then your "problem" is that Navigation/Android Auto/CarPlay volume is too low for you to notice it's talking to you (you CAN set it to 0 volume after all, independent of radio volume). So it's the audio "ducking" of the front speakers. Otherwise, probably a bug with the audio ducking and it ends up getting stuck.. They have released at LEAST one infotainment update since the 2018s released; I updated our 2018 Sport and 2019 N-Line at the same time, about 10 months ago. Haven't checked recently for an update, however.
Our '18 Sport somehow has a buggier infotainment than my '19 N-Line, not sure why that's the case. After the update I did it was significantly more reliable. Though BOTH cars tend to get that weird delayed "scratching" sound with Carplay on occasion, where I have to unplug then re-plug the phone and it's fine.