Has anyone experienced the ICE automatically starting up at a stop light, 35 minutes in to a trip?

I drive expressways and city streets to and from work (which takes 45 - 50 minutes each way) and everytime my trip hits the 35 minute mark and I am at a stoplight the engine will start up and run for 10 seconds then switch back to EV mode, or engine will start up and soon as I take my foot off the brake, the system will drop in to EV mode and then start up again when I am moving. This only happens at the 35 minute mark, not before; I haven't driven long enough to see if its every 35 minues afterwards.

I mentioned this to the Service Advisor at my first service; and the Tech said that this is normal. I have friends that have Prius, and their cars do not do this.