Should you notice the transfer from gas to electric and vice versa? My car you can feel it change back and forth, is this normal?
Yes, there is a power difference and you can feel that. If it's quiet enough you can hear it as well. As the car breaks in it will become less noticeable. But by then you will be more observant and will still feel and hear it. You can also see it on the dash with the green "eco" symbol. It comes on when the gas engine shuts down.
Completely 100% normal. Sometimes you can feel it, sometimes not. Believe me, the car will let you know when something's wrong.
If there is a big difference in power demand, like you need to accelerate, yes you can feel it, but if it is a minor increase you might notice it a bit but not feel it. Sometimes if I am just driving, I look over to the display and am surprised it has put itself into EV mode. The reverse you are always aware of due to the slight increase in noise level.