My London does the same thing except she is 8 months old. She is potty trained and goes on her pad but she has peed on her bed before too and I'm like why would she pee where she sleeps? But then again she doesn't even sleep there, she sleeps on my bed. I'm trying to stop her from doing this and she doesn't do it all the time but I've noticed that she has never peed directly on the floor, she always pees ON things, on a pad, on paper, or on her bed