Fed is in the worst of all worlds. Only way they can unwind QE with neg. bank lending and not facing shrinking money supply is if velocity of money starts accelerating. Which is obv. what they were aiming for, but it comes at the worst time and can become uncontrollable inflation
Alternatively, if bank lending accelerates (e.g. because yield curve steepens again, that would require yields at long end to rise dramatically), banks have no appetite for the bonds the Fed tries to sell, quite the contrary, which will push yields even higher. There is no win.