Strong perfume scent

Last week, at the wife's store, I was in the backroom pricing some merchandise I had just brought in. As I sat at the desk I was suddenly aware of a very strong scent, a perfume, it was not unpleasant but neither was it a scent that I recognised. Looking around I expected to see a spilled bottle or other cause for the scent; but nothing was apparent. The oder left as suddenly as it came so I thought no more about it. Yesterday, my wife, was telling me that when she made her way through the backroom she was suddenly enveloped in the strongest perfume. She said it was so strong it almost made her sick. She said her impression was the perfume had come from above and settled around her. I asked where it happened exactly and she sa,id just beyond the pricing desk. At that point, in the backtoom, there is nothing overhead but ceiling/ I told her I had experienced the same thing while working at the desk. She does sell scented candles at her store but nothing with that strange scent. But even if it had been the candles, what would make it hit so strongly and dissipate so quickly?