I have a 2009 Honda Accord. All 4 brakes were recently serviced so I don't think this is related to pads or rotors needing attention. When I first start driving, when I hit the brakes, there is a distinct gurgling / bubbling sound that comes from the brakes. After hitting the brakes a few times, this goes away, and doesn't return until the car is idle for awhile again. The brakes seem to be performing fine, and there is no "feel" of grinding or anything - it definitely seems liquidy. Reading a bit online, this may be related to cold weather, and I do live in New England so it is getting cold here.
What is causing this noise? Is this normal or does something need servicing? Obviously I could bring it into my mechanic, but I don't want to do so if this is a non-issue.