Welcome to BB Bunnychan! In terms of posting duplicate-topic posts, that’s completely fine, and actually encouraged! There’s always new experiences and knowledge on rabbit care, so we love seeing new topics crop up so active members can talk about their experiences, even if it is repeating information from an already-made topic.
First, it’d be good to know if your rabbit is spayed (which I highly recommend for female rabbits due to the astronomical chances of developing uterine cancer), and if so, how long ago. Spaying prevents not only cancer, but the territorial urge to mark — while it doesn’t rid of all of it, generally people are much more successful in litter-box training when their rabbit is spayed. If your rabbit is spayed and it was recent, there is a post-spay hormonal surge that occurs which temporarily ramps-up hormonal behavior (go figure), so it could be a “phase” she’s going through due to a recent spay.
You did a great job in putting a litter box there where she’s indicated “she likes to go”. You have some correct assumptions, in that those areas being places where she wants to go (e.g. where her pellets are) or a place where others go and she can’t claim (e.g. the door to where other family go; not cat-exclusive it sounds like), may be places she’s marking to express those intentions. It could also be that she’s simply decided that those places are also “litter boxes”, just on her own accord. My Wick has made that decision by one of my closet doors, so I tend to keep an eye out to dissuade him from doing so and thankfully its lessened in frequency (I hiss at him and move him into a litterbox when I see his butt arch).
One thing I’ve found is rabbits can be… lazy…. sometimes the act of needing to jump into a litterbox to pee is just. too. taxing, thus, peeing beside the litter box is “just as OK” — or that’s how I’ve read it. Wick’s litterbox adherence went up when I removed the high wall I put previously to prevent him peeing over the edge. Now they’re all off and although now he pees over the edge all the time, he’s going into his box every time to pee, so it’s more “contained” generally. Is there a way to make those litterboxes “easier” to go into, if they’re high walled?
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.