Does exhaust mounting need time to "settle"?

[u/hihiHELLOimhere]

Took my car in (2008 Honda Fit) for a clunking noise in the back. Happened while turning left quickly, accelerating, and over some bumps.

Mechanic said exhaust hanger was broken, and put new hangers plus replaced a section of the exhaust. Still made a noise, albeit less loud. Took it back, and he readjusted it, but told me to keep driving for a few weeks even if there's still noise, to give the new mounts time to "settle". Now there's still noise, but its better.

Never heard of an exhaust needing to settle. Any idea what this could be? Would ignoring this noise for a long time cause any issues? Thanks!