In-Transit location quantity remaining - fully shipped

Really odd situation here. I have a posted transfer transaction. The ship-to and receive qty are both 3. The transit location qty out (second transaction) is also 3, however the transit 'in' transaction has qty 4 and remaining qty 1.

Just wondered if anyone had seen anything like this before. It's on a 4.0 database which hasn't done this since it wen tlive over 2 years ago. Unfortunately it seems impossible to fix via any standard function (item journal will not allow apply to transfer document).

My idea is to manually change the item ledger entry so that there is 0 remaining qty. That just leaves the cost which was calculated for 4 items and is therefore wrong. The bad news is the customer uses average costing so I have no idea how this is going to effect that ](*,)