> Pressure reducing valves are used anywhere the pressure going into a home is above 80 PSI, and those are a lot more common than homes needing their own booster pumps
My house has one of these, as the pressure would go up to 90 psi sometimes (iirc). Weirdly, my water pressure isn't consistent and can still burst to a "visibly from the tap" higher pressure for a few minutes at a time. I have no idea what causes it.
I wonder if it's from water expanding in the hot water heater. That might be pressurizing your system after you send a volume of cold water into the heater after use. Your pressure reducer valve might be acting like a check valve preventing expansion relief into the municipal supply.
My house has one of these, as the pressure would go up to 90 psi sometimes (iirc). Weirdly, my water pressure isn't consistent and can still burst to a "visibly from the tap" higher pressure for a few minutes at a time. I have no idea what causes it.