MESSAGE FROM UBISOFT (http://forums.ubi.com/showthread.php/1774511-UPDATE-XP-Issues-in-Ghost-War)
We have heard concerns over the bug related to the amount of XP shown as being received after every match in Ghost War. Some players have been reporting that they are being shown negative XP points being earned. We wanted to take a moment to address this issue.
It seems to only be impacting players who began leveling prior to the October 24 update and is only on the player facing side. In other words, it only looks as if you are not being awarded XP properly, but in actuality you are. Our backend is calculating all of the XP properly, and therefore you should get upgrade points and unlock classes and perks on schedule, regardless of what XP you see you are getting.
This being said, this issue will be fixed in a future update, so stay tuned.
Thank you all for your patience and understanding while we resolve this issue,
Your Ghost Recon Community Team