Hi Sportivo,
That's weird and to be honest, I don't have been experiencing nothing like that. Like I previusly said, I find the 433 more prolific and it's the tactic I use the most. Right now, I'm playing a online save with a friend and i'm managing Chelsea and I'm 2nd (Liverpool didn't lose any match so far).
Also I realize that the F9 makes the movement I want him to do (with and without the ball), but don't score as much as I wanted him to do. I changed the role to Trequartista and even Giroud scored a 4 in 3 matches (before that, also playing on his main roles, scored 3 in 20...) ahah. Also make a small change onleft central midfield (Kanté) to be Box-to-Box or even Ball Winning Midfielder (support roles to be more efective on defense) and because with the striker with attacking role, doesn't make much sense to have the central midfielder with attacking role too, just my opinion.