Urinating on floor

I adopted a rabbit out to a couple about 6 months ago. Her name is Sadie. She's done great with the litter box until about two months ago, when she started urinating out of the box during out of cage time. The new owners had her spayed 2 weeks ago. I told them that should help if it's territorial marking, but that it could take up to 8 weeks. She said there's no blood in the urine and there's no fishy smell. Also, their neutered male (Hawkeye) has been urinating in the same spot that she goes. I recommended a second litter box in that area, but we were both unsure of what can be used to clean up the urine. She's been using vinegar and water, but it hasn't helped. I was thinking Nature's Miracle, but wasn't sure if that was formulated for the proteins in their urine. Suggestions on either the litter box issue or cleaner recommendations?

Sounds like both buns are territory-marking. Even neutered buns will territory mark against stranger buns. The only way to stop this is to either bond them or move them so far apart they can't smell each other. There are lots of pet urine enzyme cleaners available in pet shops, I'm sure that would do the trick.

Ok, I wasn't sure since they have different cleaners for dog urine and cat urine due the specific proteins if they would work on rabbit urine.

Oh hm there are all-pet general enzyme cleaners at my local stores. I'm not sure, but I'd go with the cat one since both cats and rabbits do marking-scent pee and dogs do not.