For me it’s something brushing against the outside. A sleeve when pulling rangefinder, putting binos back in, etc. I’m following this thread too, considering a change.
I have the 1st generation no mag marsupial. Advertised as "no loud magnet snap" which is true. However the elastic straps rub and twand like a bass banjo. Not sure how the 2nd generation are doing
I’m sure it doesn’t affect game but the small snaps and pops and groans from buckles has me replacing all of them with buckle deletes and G-hooks when I get a new one. Auto locks are awful for sound.
Honestly the best I've ever tried is the new Sitka Harness. I absolutely love it. Only one I have ever had that is quiet, with no slip or flop, and no buckle screech (doesn't use buckles).