Asphalt 8 multiplayer rating

Solution 1:

According to this Reddit thread, you are experiencing a difference in points depending on whether your opponent was of higher or lower rank than you are.

Depends on how high or low ranked your opponents are. If they're significantly higher than you and you actually beat them, you earn a lot of points but if you lose to them, you might not lose or gain much depending on how bad the loss is.

If you're beating lower ranked players, you won't get much but if you lose to them, you'll lose a lot of points.

Thus, in the matches where you got third place but your rating went down, it was likely that you lost to a significantly lower ranked opponent. As a result, your score went down.