Hi TIGGERLIT,
I can relate to what you are saying about your dog.
I have a Westie who tends to do that at times, but the Westie I had before her did it all the time.
He would hide his food, especially treats, usually in corners of the house. When we watched his carefully, he would pretend he was burying the food simulating throwing earth over it to hide it. Of course, there was no arth in the house, but he would take minutes to supposedly bury this food. Late he would go back to it.
Think it goes back to their instincts of burying bones which dogs did years ago, where as now, dogs are very seldon given bones. They get other treats instead. Hope this helps.