Litter Scratching Problem

Hi! New member here - quick intro. I have 3 kitties, oldest is our girl Trinity, a torti Manx, who was given to us by our friends kids after they rescued her from a nearby drain, we assume she is approx 6 years old now. 2nd in line is Oskar, a male silver/black tabby, who is 4 this year. 3rd is our terror, Foose (named after Chip Foose from Overhaulin), a male light ginger/caramel tabby - bought as a domestic short-hair and somehow evolved into a medium hair. I will post a pic later of the trio. We are having a problem mainly with the 2 boys using the kitty litter. They have no issues in sharing the litter, regardless of what we use, all happy to use the one tray (which is cleaned VERY regularly). However Oskar, who has lovingly taught this to Foose, wont scratch the litter after he has used it, instead scratching the wall, floor, outsides of tray, around the food/water bowls. It is like he is trying to cover his mess, but just doesn't get it!! He has done this since he was a kitten, and we have tried to "show" him how to do it, but just is not interested. I know we can move it away from the wall, so he doesnt scratch that, but is there a solution overall???? Thanks

Tell me if you find one! My boy rarely 'covers', but does all the scratching you mentioned - sides of the pan, the door of the utility room, just about everyplace except to cover up. Sometimes my girl, who always covers, will pop by to make all tidy.

I've been told some cats just never do cover - sometimes it's considered a form of marking the territory, but who knows?