Steps to reproduce:
If there is reserved and availible move for a product with full lot tracability, the transfer wizzard appears. There you can add a product to the wizard. Important thing is that the first product with full lot tracebility does get the lot removed in the wizard. This will rises an error trying to transfer. You raise the error a few times and after that you put in a lot in the first articel.
The transfer will succeed, but the qty of the product added in the wizzard will get multiplied by the times the exception raised.
Only ammounts that are entered into the wizard should get transferred.
The cause for this seems to be a write call from the wizard, without returning the ID of the created pack_operation to the wizard. So next time instead of updating the qty a new pack_operation is created.