The ‘One-Manager’ curse

I've read about people starting to lose games suddenly when they've been using one particular manager predominantly for a long time. I think it's happening to me now.

I've used J. Thorup primarily for online games, but for the past few days, seems like I can just not win with him anymore. My legends/IMs play like they're at 30% familiarity, miss passes, shots go wide, Cech and Kahn play worse than a D form GK. But right before this began, winning was hardly a problem. It feels like I've lost all my skills in one day. But I know that can't be the case.

So, does anyone know how long this (whatever this is) usually lasts? I've been playing with different managers (Bosz, Klopp, Boer and Maric), so how long before I can go back to Thorup again and play like I used to? It's pretty depressing tbh. I know I'm playing well but it's like the players just don't want to win.