New Toyota Yaris smell of burning rubber during testdrive!?

I testdrove a new Toyota Yaris year 2015, petrol, non-hybrid, 1,3 L with automatic gear, which I consider buying.

During the testdrive, sudddenly, smell of burnt rubber appears inside the car after driving out of the highway I take the car back on the highway with the cardealer once again and same thing happens, again smell of burnt rubber.
The car was driven normally. Aircondition/airvent was on.
We stop the car, open the hood and the smell of burnt rubber is coming from the engine and not the tires.

What cant it be, what do I do?

Try driving another similar car and see if it behaves similarly. It is possible someone spilled some fluid on the exhaust or it has a fluid leak, or something else. Buy a different car.

Chances are that the specific car was at fault. The batch won't be bad as Toyota Yaris is one of the best cars around.