Is it a fault though?
Presumably it’s a MHEV and being a Golf it probably also has ACT or Cylinder on Demand technology.
It sounds as though it’s doing what it should and shutting down the engine when on light loads and when coasting.
Our Audi Q3 used to do this.
Out of interest, why do you think it’s dangerous? Presumably the brakes don’t shut down too?!
2024 - BMW i4 Grand Coupe eDrive 35 Sport
2020 - Volvo XC40 T4 Inscription
2017 - Audi Q3 TFSi Sport S-Tronic