i had a problem once, the mech did replaced the pad, & to my belief it reoccured after few days, i asked him, is it normal as its a new pad,
my bike has fallen 1-2 times, so i went ahead & checked my wheels for any wheels-out, caus m using a spoke wheel rather than mag's / alloys ..
& now after quite a while, after lot of riding, as m a frequent front disc brake rider, the noise has been stopped.
so the point is that the issue couldd lie with the disc, brake pad, wheel itself