I was doing the level 27 quest out of Asoki port and for some reason even though I had the inventory space for it I got told the Ranma flowers had been sent to my mailbox.
Sure enough after handing it in I went back to the village and a duped version of the flowers was waiting for me in my inbox. I spoke to Blitzed about it but he says he's unsure how it happened...
I wouldn't know how to replicate it myself as the inventory slots were open, so I'm unsure if I need to fill them then find a quest item or not