C300eOwner

I'm driving a 2024 C300e (with around 1000 miles), and when accelerating in EV mode (30% pedal steady) I feel what I may describe as the gearbox shifting gears when passing around 40 km/h and around 60 km/h. The engine torque goes monumentally to zero (also consumption in kWh drops to zero) and occasionally a jolt is experienced.
Does the c300e uses shifts gears in fully EV mode (whiteout switching to petrol) or is this any kind of malfunction and should take it to the dealer?

Thanks!