I go to SP, I make the best, most awesome replay ever. Using uke and tori fighting dramatically. And then the last turn, I press space.

What happens? It starts a new game and I can't even save my replay, which I made whole 10minutes, but even more since it took way more time to research all the good moves.

So what the fuck is that thing? Why can't I save my replays? Am I the only one?

Setup, Options, Autosave replays, profit.

Or you could keep count, it only does it every 4th time.
And if you lose track, just shift space untill 1 frame is left and then press R or P.