Being a cat owner for many decades and knowing much about these enigmatic creatures, my new rescue kitten (about a year old), has the strangest behavior: After eating, he scratches the floor, multiple times, from different directions; exactly like he’s covering waste in his litter box. Any ideas why?
Some cats have a stronger burying instinct than others, and will scratch to bury at surfaces that are completely unsuitable to burying, sometimes even to only cover up a smell, as there is no physical object to bury.
My cat, for instance, is a enthusiastic bury-er that scratches at his litter, the sides of the box, around the outside of the box, and any nearby objects will end up in the box. He will do this sometimes even if he's not just used the box, but because he's so fastidious about burying. I've also seen him attempting to bury nowhere near his box, at nothing. Apparently a rogue smell is enough to make him want to bury.
Therefore, I have the impression that your cat still smells the food after it has eaten it, and is trying to cover up the smell by burying.