Brake question...

I have noticed in the last day or two that occasionally, when I stop the bike, like at lights or roundabout, I get a sort of a clunk or a knock from (I think
) the front brake, or at least the front end. Could be caliper, forks under compression, or something else entirely???
It doesn't happen all the time, and some hard stops couldn't recreate the problem. So it seems to be random, or I am doing something differently when I am deliberately thinking about it.
Any ideas what I should look for, or should I not worry too much?

It doesn't happen all the time, and some hard stops couldn't recreate the problem. So it seems to be random, or I am doing something differently when I am deliberately thinking about it.
Any ideas what I should look for, or should I not worry too much?