get rid of the litter tray, she may be seeing it as dirty (even though it wouldnt be to you or me) so is finding another clean place to do it.
I got rid of our tray as soon as both were not kittens anymore, and they ask to go out.
They are almost as good as the dog, but a few times when one has accidently been locked in they have found an alternative place to go……
the bloody bath!!!
I hate that feeling when you open the front door and you smell that smell and have to play hunt the shit.