Potty Problems

Here's my problem. Isis REFUSES to cover her poo. At all. She'll dig prior to going poo, but after its out of her, she has no more concern what so ever with covering her fecal matter. Any ideas? Suggestions? It'd be greatly appreciated!

my stubby is the same.
uncovered poo smells terrible!
he will dig prior to going but just hops out of the box immediately after.
he will sometimes scratch the outside of the covered box afterwards but never buries.
i tried to show him by covering it up with his paws but he seemed scared so i have just let him continue.
OG covers no problem.

My Cynni doesnt cover anything... she turns and looks at it like " ewwww" and jumps out of the box... THEN my 11 week old Gizmo runs over to investigate and covers it for her.... he has even gone as far as to punt her out of the box so he may do his "job". but before he came 3 weeks ago... nothing was ever covered! Why are some cats like this?

Jade gets disgusted and also cleans up after Isis LOL. It's funny but very annoying at the same time. Any senior members or anyone with a similar situation have any words of wisdom?

If you have a covered litterbox, you can try remove the cover. I don't know if it's the cover holding in the smell or the fact that once they are out they can't see it, but it seems to help. My kitten used to get scared of his poo and explode outta the box meowing and spraying litter everywhere.