Could it be that somehow inworld 100%-love cats that haven't been assigned a mate, do what cats do best and just mate on their own behest (sometimes)? I've just had for the second time a new born kitty box from two live cats when I had not the intend to mate these cats (yet).
Of course I could be wrong, but it's not likely that in a moment of absentmindedness I had assigned any mate when I had no plans to do so. Especially the first time it happened, it were two cats from total different breeding lines that should never have been bred together. They were both waiting inworld while I was raising new born kitties in the cattery as their next mates. And then they produced a box. And now again with two other cats.
I'm a bit puzzled.