2015 QX50 A/C Smell

[alawi0]

I have a new 2015 QX50 with only 1000 miles. Sometimes the air that comes in from the vents when the A/C is off smells bad, something like feet! This sometimes also happens when the A/C is turned on. The thing is that I haven't been able to find a specific reason or time when the smell comes in. This happens around 20% of the time and it only lasts for between 20 seconds and 5 minutes.

One thing that could be causing the problem is that I used to park the car for around two weeks under trees. So leaves and little woods covered the hood. It was then cleaned by the dealer and I never parked again under the trees.

Anyone had such problem? What your guess would the problem be?

The dealer (without any inspection) is suggesting to replace the cabin air filter! I guess that if it is the cabin air filter, then the smell would be continuously coming out. But it comes out for a short time then goes away.

Thanks!