I don't think it's the tactic or updates mate. It happens to me as well with my Dortmund team unfortunately. Up until February / March, the team is performing brilliantly & then all of a sudden, they're playing like Amateurs! Some say because the opponents (i.e. the Match Engine) 'learn' how to deal with your tactic. But for me this doesn't make sense at all. I believe it's more something sort of built in FM to make you swear & bang your head to the wall!
Happened to me with different good tactics like this one, Twister & many others. Now, what I tend to do is keep another 2 'known good' tactics in the slots, like for example Conqueror & when February / March arrives, I usually switch to them & generally, I manage t'o keep some sort of consistency. Not always but anyway.
This thing has been driving me crazy for a while tbh & I'm glad to hear it's not happening to me only!
i'm glad its not just me then too, I had a good lead in March so managed to snag the league just! fizzled in both FA cup and Champs league. ive tried a few tweaks here and there but see a knack of dominating possession and shots, but losing 3-0 when the opposition only has 3 shots...
i'm going to have to try another tactic, my lineup is top top, 86million for Pogba and he is getting the runabout by Jordan Rossiter at home ha! any recommendations for good tactic's?, this is the first I have used on 16.3...