Yes this is normal. Once the water flow is stopped at the sink, the pressure needs to be restored in the water lines. Although the water is not really compressible, the plastic water lines will expand a little. Dead ended lines with air trapped in them, like unused laundry faucets or outdoor showers, can also act like an accumulator.
2014 Cougar 313RLI
2017 F250, 6.2L Gas, Crew Cab, Short Bed