Injuries for substitutes after being 2 minutes on the pitch have been observed enough times to conclude that this has been programmed to occur as such in this game. I have had 1 injury like that last season, and also someone else has reported something similar on the forum here.
I have also noticed that an injury is more likely to occur after you have made the third and final substitution than after the first or second substitution. The probability of this being a coincidence is low; hence, again, it is likely that this has been programmed to occur as such in this game.
About 'trolling', I think that randomness has been given too much significance in deciding the outcomes of matches in this game, which is why there are so many unexpected or non-logical results.