Rabbits uses urine and faeces for both elimination and as marking, so they may be demonstrating their territory by “poor” litter habits.
It’s also entirely possible that they don’t know where to toilet or at some point they didn’t and now the pee in those extra spots out of habit.
If you thoroughly clean those areas with either diluted white vinegar or a commercial product to break down urine the area may seem less compelling.
Rabbits also like to pee on soft surfaces and surfaces that smell of others so if you are using blankets or rugs and/or the items in their cage smell of others they may feel compelled yo wee on them. Although 11 weeks is quite young for spraying.
The best thing to do is to make sure the other surfaces in the floor are solid, I.e the cage bottom (unless it is wire than you must cover it) to reduce temptation. If you have no luck with thus, try putting litter trays where they are peeing and then gradually moving the trays closer to the one you want.
Paper is both poor at absorbing and awful at neutralising smell. I ran out of litter recently and had to use toilet paper – the smell was horrendous!
This a good list of litter types (scroll past the box types): http://www.sandiegorabbits.org/litter-box-training/safe-litter-box-materials
I use care fresh but lots of people use wood stove pellets as a cheap and absorbable alternative.