rabbit peeing outside of litter box

(terrible quality picture of the criminal in my laundry basket for funsies)

in the past year or so my bunny has really regressed on his litter box habits 🙁 he used to be pretty good, but lately it seems like he’s peeing outside the litter box more often than not. most of the time he pees right outside the litter box. i know he doesn’t have a problem jumping into the box because i see him in there all the time to eat hay, but this morning i saw him jump into the litter box, grab a piece of hay, and then jump right outside the litter box to eat it. i’m wondering if he’s doing that and then peeing while he’s eating?

is there a reason he doesn’t like his litter box anymore? i use pine pellets as bedding, and he has a pretty big box relative to his size; it’s probably like 15×20 inches and he’s a 4lb holland lop. he is getting older, he turned 6 in may, but i dont think he has any mobility problems because he loves to jump on the furniture.