To be fair models do differ in this. My RC will always revert to Normal mode and will allow one to use EV mode when the ICE is cold, as long as one presses the buttonn before the ICE starts up (approx 10sec, up from 2-5sec in my 1st gen RC)
That all said there is no problem with selecting to ECO from cold equally no problem selecting Sport+ if desired. If there were the car wouldn't allow it!