There's a man in England who forgets every 30 seconds. He says he's waking up for the first time in years, as if nothing was before that; just blackness. He remembers his wife, etc, but he doesn't know that the Berlin Wall came down.
What they've found is that he has some form of "unconscious memory" where he's forming new memories, but doesn't consciously remember them. For example, he'll watch a movie and then when he watches it again, he'll say he's never seen the movie before in his life but he'll be able to "guess" the ending, just like someone with this condition can improve their tennis game but just attribute it to "beginner's luck."