A wanted safe haven is not the same as a wanted permanent home.
As I have often repeated the danger is that US confounds the eagerness of markets in finding a temporary safe-haven with a willingness of capitals finding a new permanent home in the US and that is as we all should know a totally different animal.
Also there is a clear and present danger in not being able to access the real market signals since the current rates out there have nothing to do with the rates required if the Fed was not doing so much buying. In some ways it is like a bank participating in buying some securities in order to make the harsh mark-to-market truth easier to digest. It only works over a short period of time.