Whilst I agree it could be partly OC if you do not stop and deflect the activity, there is a possiblity she will start scratching up elsewhere, like the carpet, and that may create an issue for you. It is natural for dogs to "nest". All of ours do, some more than others, but usually is limited to trying to change the shape of the stuffing in the dog bed, or digging a hole in a shady spot.
When she starts digging the tiles, immediately call her and offer a game - tug, fetch, whatever and reward her for stopping digging.
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