I know that EA cheats me with forced losses, I'll have 5 wins where my score is about average, then I'll have a loss where my score is something like 15 to 25 standard deviations below the mean. After that forced loss, I'll have 5 more games where my scores falls within 1 standard deviation.
I always assumed that the names on the league board were actual players, but EA is so duplicitous and underhanded, they have no credibility as far as I'm concerned and I wouldn't put it past them to have computer-generated names occupying the slots in the rankings.
So in addition to the forced losses, I wouldn't put it past EA to just contrive rankings for faux players to bump real players down in rank to reduce the amount of gems and mints that they receive.