Ding-dong instead of voice direction in Apple Maps

Hello,

When driving with Apple Maps, sometimes the voice directions are suddenly replaced by « ding-dongs ». This is extrememy annoying and even dangerous. All the voice and volume settings are correct, I don’t play background music or whatever, it just seems to be random and when it strikes, I haven’t found a way to get voice back (starting again the navigation or killing Maps app does not help... it will remain like that until at some point voice comes back on a next navigation...).

is there a rationale behind this absurd behavior? Is there a way to prevent or fix it?

thanks in advance,

Rémi