I know you guys don't really deal with this stuff in California but the moisture on the glass does come back. When you are breathing in the car and it's cold outside, the moisture in your breath collects on the window.I do not see how the rear window defroster could “distort” the glass. The shape of the glass is not being altered by the heat produced by the defroster wires.
That is a reasonable explanation.
To those who think that replacing the rear window glass will effect this issue: I think that is very unlikely.
If you can’t see out the rear window because of moisture on the glass, turn on the defroster to get rid of the water and then turn it off as soon as it’s done it’s job. Don’t leave it on.
Learning to live with this shouldn't even be part of the conversation. This simply should not be happening, period. I've never been in any other car that does this. From my first car (a 1986 Honda CRX) to my 2008 Acura TL or my 2014 Hyundai Sonata, i've never seen anything like this.
If it is the heat from the wires in the window causing an optical illusion and distorting my view, then turn the fricking heat down. This should be a simple software update for Tesla to do.