My front brakes make a clunking sound when applied at low speed, for example when backing out of a parking space. The pads and rotors were recently replaced. The behavior at high speed seems normal.
So you pull forward into a space applying the brakes…
Then you back out of the space and they clunk?
Do they clunk when you move forward after the reverse and apply the brakes?
If that is so, have your brakes checked by the shop that did the work. If they used budget (cheap) pads, they may not fit tightly in their carriers so they clunk. Or the mechanic may have left off the insulators that fit between the pads and the carrier.
Either way, you need it checked out. Brake strangeness is nothing to ignore.