1. Use 315p for carrying cargo
2. Load the cargo into the cargo grid, especially closest to the cockpit
3. Arrive at location for offloading
4. Cargo is stuck to cargo grid and cannot be offloaded with tractor beams

What happened
Sometimes cargo gets stuck on the cargo grid. It cannot be lifted off of or forward or backwards from the two cargo elevators. This seems to be especially the case with the grid closest to the cockpit, but it has also gotten loosely packed boxes as well.

What should have happened
The cargo should easily release from the cargo grid as with all the other ships.

Workaround
Sometimes if you let a tractor beam work on it for a long while it slooooowly moves up. Very rarely you can then get it out this way. Other times I have glitched into the box from the cockpit side and was able to sloooowly push it off the grid. Sometimes storing and reclaiming the ship might dislodge one.