You would get maybe one troll result per season if you were unlucky up until the last 3-4 months where troll results are now far more commonplace.
I don't think there is any doubt that the game algorithms have changed adversely for many creating the likelihood of a troll result. We all recognise the signs, usually starting with the opponent GK being MOTM with a 10.0 rating.
The Managers who say they haven't been affected by a troll result are incredibly lucky. In my 6 years in this game I have never seen it so bad or as many complaints as the last few months.