I don't know about the propellants, but you're probably doing yourself a disfavor if you are using an oil spray on nonstick.
The problem is that you're using way too little oil with them. It won't matter if you're making stir fry, but people tend to plop a single piece of meat or fish on the pan. Then what you have is vast ares of pan bottom, hot, covered by nothing by oil. What happens is that the oil polymerizes, just like in seasoning a cast iron pan. You end up with a tacky gunk which is sticky enough to have a grip on the teflon. As you cannot heat the pan enough to actually make a good seasoning out of the stuff (and it won't work well on top of nonstick anyway), you end up with mini droplets of sticky substance on top of the teflon, which reduce the non stickiness.
The oil is also too little to prevent the pan from overheating, which means that your pan can get destroyed by the heat itself. Use an infrared thermometer to see which knob setting is low enough for your pan and only use a naked or sprayed pan under that setting.
I don't have any studies about that, I've just made a similar mistake to my own pans and have seen enough of my friends' and relatives' pans covered in that oil residue to know it's a common problem.
Of course, this problem is not inherent in the spray. You could spray until you have enough oil to not get that effect, a depth of at least 3 mm of a continuous oil puddle seems to be sufficient. But if you are going to use that amount of oil, it's easier and cheaper to get it from the bottle, not out of a spray can.
It is possible that there is an additional problem caused by the propellants. Or it could be a wrong theory by the people who notice the negative effects of frying on a sprayed non stick pan and don't know enough about pan seasoning to recognize the process I described before. My guess is the second, as the whole point of teflon is that it's as close to chemically inert as they could get. I'd like to see another, better sourced answer clarifying this point. But for me, the above problem is reason enough to keep the spray for other purposes, no matter what the propellants do or don't do.