Rattling Noise when braking at low speed for '98 Camry

This is a 1998 Camry XLE V-4 sedan with about 80,000 miles.

It was sent for a brake service recently because it would vibrate when braking at moderate to high speed. Rotors were replaced and as I drove out, I heard this rattling noise after applying the brake and car was about to stop. I drove back and the mechanic said it was expected but he could adjust it to reduce the noise. He said the noise should be gone in a week. The noise did seem to be less but it did not go away after 2 weeks still. The noise only happened when the car slowed down to nearly stop. I plan to bring it back soon but I'd like to get some validation from you to see if this is indeed an expected behavior when a new rotor is installed and such noise should go away in time. Operation wise, it seems to be OK but the noise is plain annoying.

THANKS!