My first thought is what eggman already posted. The 2 rearmost rubber exhaust hangers wear out on the body side. Quick test is pull the rubber off and put a few wraps of duct or electrical tape on the metal rod and put the rubber back on. They changed the exhaust setup for 2017 and this is the result.
The other possibility is a loose belt, but they usually chirp under hard throttle where the loose exhaust hanger would do it under light load/acceleration.
If you want to keep your cvt lasting I'd recommend replacing the fluid at 30k miles. I used to say just pull the plug which is usually good enough and you'll get about 2 1/2 quarts/liters out. Jack up the back of the car and get almost another 1/2 quart. With our cars at work being used for work we need to follow the severe schedule and when we had a warranty issue with one the dealer claimed pulling the plug isn't good enough and had to provide proof of dropping the pan among other non-existent impossible things like a transmission flush regardless of what the factory service manual says.
Regardless it's not a bad idea to drop the pan and look for bit's o' bearing and change both filters. With really high mileage over 200k miles start looking for low mileage used one cause the odds are against you.
Originally Posted by fred101
View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 35.1 mpg (US) ... 14.9 km/L ... 6.7 L/100 km ... 42.1 mpg (Imp)