I noticed that current cup fixtures in the first round after group play are completely random.
I think it is not fair that if you win the group, you get to play tougher match against the winner of another group, while the runner up plays against the weaker club (also runner up).
And, probably not so important, but still awkward when it occurs - to avoid meeting the club from your own group already in the first round of elimination. Once it happened to me - after I played against the club in the group stage, I immediately had to play against it again in the first round of elimination stage.