Will it hurt the ICE switching from EV to HV while doing 65mph?

Yeah, I'm 9.5 miles each way. I could actually do a round trip and a one-way except during the hottest times when the AC works extra hard. My seasons are flip-flopped from yours. I'm very curious about what the next Prime will bring us.

 

There is no mechanical gear changing in a Prius (Prime or regular Prius). It's all done with the computers controlling the motor-generators (MG-1 and MG-2). This includes reverse. There is no mechanical way for the gasoline engine to move you in reverse; only electric motors can do that. Shifting into Reverse at speed is interpreted by the computer to go into Neutral. The mechanical part of the Prius gear train is incredibly simple. No gears or belts or clutches engaging and disengaging. The complexity is in the control software.(The Prime does have a "clutch", but it is simply a one-way sprag clutch that allows MG-1 to move the car without the gasoline engine being turned backwards. Turn it one way, and it locks up and power is transmitted to the other shaft. Turn it the other way, and it freewheels. No friction plates or anything like that.)