Guest not receiving mission control completion reward

Apologies if a duplicate bug
Platform:
PS4
Description:
Booted game up with my friend for the first time, both landed on the shore together so right from the beginning. My friend seemed to be levelling a hell of a lot quicker than me. So decided to look into why and noticed none of my quests where actually completing. In order for me to got the XP I had to load onto my own save and complete the missions for the second time…

Really enjoying the game so far but it’s starting to put me off
Players in your game:
2
Specifications:
PS4 pro

As per in-game tutorial about MP saves:

With that above, i wouldn’t say there’s an issue with MP saves.

Also, your friend could’ve unlocked Inquisitive Mind skill, which will give 50% more XP from missions at level 1 and 100% more XP from missions at level 2. With Inquisitive Mind skill at level 2, bare minimum you can get from missions is 2000 XP and that alone is enough for faster leveling up.