I was doing the Papulatus prequest, The Replacement Time Energy, which requires collection of two unique quest items: Mysterious Powder and Tachion. I can see the item drop from the appropriate mob, but when I try to pick it up, I get the loot message "You can't get anymore items." If I change maps or channels and return, those quest items are no longer visible to me. Other items of note: I didn't have this part of the quest in progress until I accepted it today. I did have a small number of these two quest items in my inventory when I accepted the quest today (from a previous attempt at the quest a while ago), though dropping them and restarting the quest seems to have no effect. (P.S. There should be a space between 'any' and 'more' in that loot message )
I had this issue with one of the lost tower quests in Ludi. I was able to collect 2 of the walnuts I needed and then I was unable to collect anymore, had to forfeit quest.
It's a message from the client, so I can't change it. We're re-working the quests atm, this is part of it, and will (hopefully) be fixed soon.