For this issue, you won’t be able to find an explicit patch from RnD. But patch 152159 resolves the issue even though the bug description identifies something else.

Test case:

A- Using the Register Direct Delivery window, user enters delivery of partial qty or few lines out of multiple lines. For example: user enters 1.4 qty in one line out of many lines shown (queried to) in Register Direct Delivery window  

B- After that, staying in the Register Direct Delivery window (same session, window not refreshed), user now enters 2 qty in a different line and conduct register delivery. 

Now when you check the Purchase Order Receipts, Purch Arrived Qty in scenario B, it would be 1.4 not 2 (does not have any conversion) which is incorrect. 

This happens because below Attribute String does not updates when you are performing B, so that it takes the values of A.

This is a critical issue and if the PO is invoiced and authorized, impact would be high.