12 weeks is exactly when hormones kick in!
Right now I have a bunny waiting to be spayed and though she never poops in the rest of the house, recently in her condo she likes to leave me presents everywhere even though she uses her box, I know it will pass but for now I’m 24/7 armed with a dustpan and brush! My other rabbit had perfect litter habits literally the day he came home fro being neutered, it was magic!
Most vets won’t spay till 5 or 6 months with females so I’d call your local rabbit savvy vet and check what they say, you will have a few months of the pooping everywhere to deal with and then once she is spayed her hormones will calm down and the need to constantly mark with poops will leave.
During this time bunnies can be very naughty as well as poopy, the urge to dig/chew/destroy and just be massive crazy poop and destroy monsters is driving them wild (which is why many people give up on them as they don’t realise this will pass!). Even if you don’t have all these problems, it is recommended to get your rabbit spayed because females have such a high chance of developing cancer without it plus you can’t get them a friend either unless they are spayed/neutered.