On the landed cost setup (P41291), do you have the flag "Include in Cost (Y/N)" setup as a "Y"? If so, it will be included on the item cost, so if the PO line you are receiving has inventory interface, it will go to item ledger as well. That should work perfect if you receive and then void the receipt.
did you find out the root of this issue? I am facing a similar scenario as you said. On the landed cost setup, I have the Inventory flag marked as Y but it has not been reversed from the Kardes (only on the GL). I noticed that it is happening only for a range of GL CLASS. Not sure if it is the same scenario as yours.