If its a safelight and buzzes, it sounds like a sodium safelight. If so it's perfectly normal. If it's a simple incandescent bulb as in Kodak, Ilford etc safelights for B&W then, no, I don't think it should buzz
I am not sure about the sodium, but according to the web site "cold cathode lamps" are used and must be similar to an enlarging cold light." I assume it is normal than.