Good thing that you guys were able to figure this out by yourselves.
Just in case that somebody has the same problem in the future, here's how to do this:
1) Go to the settings of PS4
2) Select saved data management
3) Open saved data in system storage
4) Choose the upload to online storage / copy to USB storage device option
5) Choose the save file that you want to copy
6) On your friend's PS4 you can access your save file from saved data management but instead of copying the save file, just move it to the system storage from the cloud / USB.
It's time to squash bugs and chew bubble gum... and I'm all outta gum.