Garden Warfare 2 missing character upgrade

So I unlocked the ammo upgrade for Z7 imp and when I left the multiplayer match after it finished my levels went down. I checked to see if the upgrade was still there and it was. I tried to take it off and apply it again and it went away, I grinded to get the levels back to see if I can unlock it again and it wont come back. What am I supposed to do? Am I just not able to obtain it anymore? Any possible fixes for this bug?