Seatbelts light problem ML

Hello,
I have a slightly annoying problem on my '02 ML 320.
The seatbelt light (and associated beeping) will not go away even after i buckle my seatbelts. It will eventually go away after its standard time, but i would have expected it to turn off the light and beeping as soon as i push the buckle in. Is this normal behaviour or do i have a faulty switch in the latch that is failing to recognize that the driver is buckled in?
thanks
-ajay