The precision was limited intentionally. From the FAQ:

    To make it less useful for snoops, the spatial and temporal accuracy of the data
    has been artificially reduced. You can only animate week-by-week even though the
    data is timed to the second, and if you zoom in you’ll see the points are
    constrained to a grid, so your exact location is not revealed. The underlying
    database has no such constraints, unfortunately.