Answer (first posted by @DWFII , a bespoke shoemaker): I see a lot of cracking in lining...although it's never as bad as on the uppers simply because the dust isn't there. I've said this repeatedly here (and some will probably be bored by the repetition) but in my part of the world much of the dust is ground up (microfines) of volcanic glass from the Mount Mazama eruption 5000 years ago. Yet the dust looks exactly like any other dust. Try to the damage what ground glass will do in a crease.
IMO, the salt itself is not making the leather crack, it's just drying it out. Putting conditioner on the linings counteracts that drying.
Also people perspire at different rates and their perspiration may contain more salt (and other corrosive minerals) than other people's.
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