I've hit this issue and according to research it has been reported by other people using Waze Android Auto on VW Group cars.

In my case I have a Skoda Superb, and when using Waze Android Auto navigation, the instrument cluster will often(/always) show incorrect symbols for turns.

It seems to mostly go wrong for roundabouts, which the UK has many of. Roundabout direction icons will either incorrectly show as just a turn, or in the worst cases a right turn at a roundabout will show with a U-turn symbol.

This confusing display has been enough to stop me using Waze, I'm using Google Maps instead.