I just played two times against a t50 deck with Hope and Ray of Light and got the same problem both times.
Hope worked as intended as long as my own damage was >N. Once my opponent blocked the entire damage of my cards he became invincible. In the first game his Hope with N=22 blocked the damage of 5 Immortals and 4 Phase Dragons. In the second game I was able to play a Phase Dragon early (Hope N=3, I dealt 5 dmg). Next turn he came up with a couple of Ray of Light so N=8, my dmg was blocked. I played one Immortal (Hope still N=8) no dmg at all.