I don't know about the older CVT models, but the newer models don't have a dipstick for the CVT transmission. So you can can't check the levels, even if you wanted. Hope there's a good reason for that, because seems dumb to me.
I have heard this before and my own dealer said they've had cases like this many times. This is apparently a common mistake when people try to change the oil in their own car. The plugs look similar and aren't far from each other. I suspect this is what killed my CVT. I went to Valvoline for an oil change in the morning, drove about 100 miles, and it died that night. Guess who ended up paying for that? Me