I experience this ALL the time. There's NO consistency with a player from season to season.
Second, I go through a pattern: start the season like **** (perhaps there IS a team cohesion factor programmed?) , around midseason once I gain lead in league, I go through a 3-4 game slump so the league stays close., Then at the end of the season when I have the chance to clinch, I get another minor slump with a couple draws and a loss before closing with a couple wins.
Again, and again, and again and again.
Formations and tactics don't mean ****. i think I could just use ANY random placement of players and not affect results.