whats going on with leverkusen? mainly inconsistency?
It's just the way of Bundesliga. Leverkusen are a very good pressing team and that usually works very well against teams who want to play football, but once you're considered a top team clubs get all cynical against you and then you need a patient approach to break defenses, while at the same time the horde of pressing/transition teams love nothing more than to exploit every little mistake an attacking team makes.
So unless you're executing a dominant approach very cleanly you're fecked either way, because your choices are between engaging in a midfield battle where nuances will decide matches (=> submitting to randomness) or to try your luck in attack and offer space to teams who specialize in puninshing just that.
Leverkusen have opted to attempt the second, but couldn't pull it off (too much risk, too little penetration) and now they are in a difficult stiuation with a lot of pressure on everyone.