Weird "gurgling" brake noise?

Hi guys,

First of all, my brakes sound normal virtually all of the time, i.e. quiet. However, I noticed today during traffic jam that when I'm coming to a full stop from a VERY SLOW speed, my front brakes will make this gurgling (not scraping) noise when I depress the brakes to about 90% of the way. It's hard to reproduce, but is almost consistently heard when the traffic is stopping and going and moving at about 10mph.

As soon as the traffic speeds up and I start driving normally again, the sound is gone completely even when I make complete stops at traffic lights.

Has anyone experienced this problem? My brakes were changed just a year ago (barely), and my driving style is average.

Any help would be appreciated. Thanks!