Vanishing incense

[Xali]

So:
I was taking a merchant's incense to Lop Nor for her... I have arrived at Lop Nor... and I have no incense. I definitely didn't trade it along the way, and I was pretty sure I didn't sell it by accident, so I checked and I haven't sold any since I was in Arikamedu. It was definitely there at the last town, and along the way, because I got several offers from passing traders on it.
Help?

Update: there was the right amount of incense for the quest available in Lop Nor (not mine, because again, the last time I sold it was in Arikamedu), so I gave up and bought that for a ton of money, but my quest thing is still insisting the quest doesn't exist. And now it's gone.

This sucks.