I've been using attacking mentality over the past 2 seasons without any issues.
Had been having trolled results earlier this season though, loosing to teams way lower quality than me (3 star difference), which other team (also lower quality than me) manage to beat 10-0. I was knock-off the CL and CUP early which the above had greatly contributed as well.
Subsequently, I started using Defending Mentality with Counter attack (even against much weaker teams), and have not been trolled since. Not sure logically if changing the mentality works, but it sure helps.