Many cats show this behaviour. If they are not hungry, they will make
an attempt to bury the food, much as they would do in the wild. Burying
it will mask the scent to some extent to stop other predators or
scavengers getting to it and eating it. As its such a natural instinct
for them to do it, even domesticated cats still exhibit this trait, not
all of them, but a fair number do.

I would not worry about this behavior, its perfectly normal.

The Hermit.

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