Most probably the pads were lightly rusted to the discs. If you are lucky the pulsing will go away after applying the brakes several times relatively hard to get rid of the rust traces.
Not to apply the hand brake is good but don't use the foot brake either if possible. If the brakes ar applied and the the car is left standing the pads tend to stick to the discs especially if the brakes are wet or if the environment is damp. It is good practice to warm the brakes up after washing the car to get the discs dry if the car is left in the garage afterwards for more than a day.
