No voice prompt for navigation in Australia?

Hi,

I live in Australia and bought a Forerunner 955 solar. I use the navigation feature for exploring new running tracks around my town and was always annoyed that there are no voice prompts on my headphones and only on my watch with quite a delay. 

I spend the last 5 months in Germany and was extremely surprised (and happy) when I used the navigation feature again and suddenly got voice prompts ("Turn left", "In 50m turn slight right", etc.). I thought that there might have been a software update without me realising (I am on v.19.18). Once I got back to Australia the prompts were gone again. 

I did not change a single setting since I got the watch and tried to change the prompts the last day without any success.

TopoActive maps for Europe and Australia are up to date. 

What could be the reason that I don't have that feature?

Cheers,