Traction Battery drops 1.2 instantly when AC is turned on

I assume you mean 1.2 miles of estimated range? If so, then yes an estimated reduction in range is normal when you draw more from the battery. The a/c is electric. Asking for heat will show an even greater reduction. Seat heaters typically won't register a reduction in range.

 

It is normal, with the AC and Heat on

 

The Prius assums that you'll keep the AC on. So it calculates/estimates the electric draw over the next 1? miles and subtract that from the current EV estimated range. You get a similar reduction in estimated EV miles when you turn the fan on (no AC).

 

these are all incorrect. you get a reduction (not necessarily 1.2 miles, when you turn the fan on, and get it back when you turn the fan off. it has nothing to do with a/c or heat. it's just toyota's very poor way of letting you know that you may get reduced miles. but of course, only the a/c will actually reduce your range, not the fan, and definitely not the heat, since the engine has to run to provide that.