One thing that I found that helped my bunny with her littertraining was when I completed the NIC enclosure around her cage- and her cage is open to it when I am home (which is alot). In her mind, her territory increased by quite a bit. She is not as naughty on the couch now- but still needs to be watched. I guess she decided I can have the couch because she is happy being queen of cage and NIC land.
I thought increasing her free space would increase her peeing outside the box- but I was definitely wrong. (I have only had her for about 6 weeks- so she is about 4 months old now). I was wanting to make sure she was big enough to jump out of and into cage using a “step” and that she was confident enough to be on floor level with dogs. She was so used to the dogs- she thought nothing of being on “their level” and she enters and exits cage like a pro. So I found out I was just being an overprotective Mom.