Don't know if this has been posted yet, but sometimes when I withdraw an item from the common bank it doesn't show up in my inventory unless I quit and log back in (I tried piping). It's happened twice today, and both times have been mid-quest (Pioneer Spirit).
Piping wouldn't help because the client never asks the server for any data again, regarding player inventory, unless you change blocks. Could be a bug... or it could just be lag.
The client does check in with the server when listing the contents of the bank, but not during the actual withdrawal phase.
I've said many times over, PSOBB is badly coded for a game that is supposed to be server-side. 90% or more of what happens, actually happens on the client side.
If it becomes wide spread, then I'd guess it's a server issue. But not every little anomaly that happens is the server's fault.
If you can reproduce this issue, you should take more details, such as if it happens with a particular item type, what you do just before it occurs and so on. Just saying "I took something from the common bank during the quest" doesn't help out so much. I mean, yeah, there's some detail there, but hardly enough.
It MIGHT be with how inventory slots are added/subtracted for placing the item in the inventory. Like by example if I remember correctly items disappear from the bank because a item overwrites the slot for another one, so along that train of thought kinda...maybe it's not updating that slot client side correctly? idk im taking guesses lol.