From where I see it, all modes have a MASSIVE balancing issue, however in Breakthrough and Rush it is the most obvious.
I can confirm that most of the time in Breakthrough (if I am forced to play it through my party) we are defending.
Playing Breakthrough or Rush where I was on the attacking team, is a rare occasion.
Apart from that, you A) get stomped or B) stomp. There is most of the times no balance in the game (also can be seen in Conquest quite a lot), causing the game to be completely one sided. I would even go a step further and say that the matchmaking actively engages mid game, and alters the games' mechanics to tip the game in the different direction. I simply do not have another explanation for games going south mid game, causing you to lose by great margin although the game was balanced the first half.
The matchmaking (balancing and ATK/DEF is not working properly. Obviously.