trailer brakes

This is the first time owning tandem trailer for a boat,the are electric,The question is when i step on the brake there is a brief second that they sound like they are rubbing they it goes away,when i take off again they make the same sound for a second.is this normal?
the make of the trailer is shorelander
thanks in advance

[TomP.]

Not sure how much you use your rig. Sitting the drums will rust up and you will get a scratching noise when they come on or go off until the rust is worn off. It allso could be your brakes need adjusting and what you are hearing is the magnets coming on and going off. The magnets rub against the inside of the brake drum to apply pressure to the shoes.