[CLIENT] Match history will frequenlty only record only the rating or the exp gain instead of both.

The match history section of the client will frequently not record both the "Champion Mastery Score" and the experience gain for the match and will instead only record and display one of these.

1. Play a number of PvP games
2. Go to Profile>Match History in the client.
3. Observe that a number of matches will randomly not display one of these records.

This is a frequent and long standing bug.