Yes, similarly experienced the weird smell from the air-cond vents when starting the engine. I experienced this previously and didn't think it was a serious problem so I didn't highlight this issue when I serviced the car at the service centre. However, during the 20,000km service, after the odour filter was replaced, it appears that the bad smell was gone. But just recently, the smell came back again after 6+ months.
Have you gone through the 2nd service (20,000km), and if yes did you notice the bad smell disappearing after the odour filter was replaced?
I can't definitely say if the odour filter is the culprit yet, but if the smell disappears after the odour filter is replaced during the 40,000km service, then it is likely the odour filter is the cause of the bad smell. (Currently the odour filter is replaced at a service interval of 20,000km, 40,000km, 60,000km, 80,000km and 100,000km)