Jan 29, 8:00 p.m. cst this happened to me also. several times in a row.
This happens to me almost every time I use the app. The difference for me compared to the previous description is that if I allow the buffering to continue I get a notification that I've been disconnected from XBox Live. I'm then prompted to sign in. If I do that then the Hulu Plus app relaunches. If this happens once during a program I'm watching then it always happens again at least twice. Very annoying.