I also noticed that Recent SP does not reflect cargo transfers either otherwise a new field would maybe not be needed?
Sounds like a bug. In 2.5 for me the "Recent SP" shows the cargo transfers just fine.
Are you sure that the cargo load/unload happened within the same 5 day Construction Cycle (or whatever timing you use)? Based on the screenshot with reserve amounts + 1 mining cycle in stockpile it looks like you just missed it.
Colony:Cargo Ship:What is bugged/not working though in 2.5 for me is minerals recieved by Mass Drivers (minerals sent away is shown properly).