Here is what his condo looks like so you can get an idea of what im talking about. This was before the cage was fully done a year ago so there is carpet on all the levels now. He has a hay box on the back of the cage (middle level). My question is:

Just recently, like 2 weeks ago or so he started to poo and pee on the carpet while eating his hay on the middle level. He is fully potty trained, has a litter box on the bottom level as well as outside of his condo. I tried to put another litter box on the middle level where his hay is and he is just not having it. He will just get mad and throw the litter box off the platform lol. It is getting to a point where I have to remove the carpet, dump off the poo and clean it everyday.
I came up with an idea of maybe drilling holes in the litter box and using metal clips to attach it to the back of the condo with his hay box in front of it. Also I am going to replace all the soiled peg board and carpet. Do you have any suggestions as of why he is doing this or anything else I can do. He doesn’t like to keep his litter box in one spot on the bottom level either. I have had him for 2 plus years and he has always been a rearranger, but this is something new with poo’ing and peeing on the carpet in the condo. Thank you 