My GTS86, the standard head unit for Australia, won't remember its configuration for the spoken speed warnings.
It worked fine for two years, then in the last month it has been giving me the spoken speed warnings. Considering the speedo under-reads by 5 kph through the range, I am often showing 5 above on the speedo and the nag voice chimes in.
I keep disabling it in the settings menu, and it remembers the setting until I turn off the car. Next time I start up it's back to the nag voice. I don't know what made the sudden difference but it's very annoying.