I am in season three and I won the CL last season. My opponent who is now on the first place in the group did not win the champions league last season. He himself is in season 4 (+1 league above me) so maybe he did win it as well but are you really sure that this is taken into account?
Do you think I/we should report it? I dont want to play in the next round versus the #1 from the other group...

Although I guess there is nothing to do but maybe it is really a bug and/or we could clarify the mechanics.