When i type /cnd all while i have leather in my inv, it converted to leather boots. But unlike /cnd all, using /cnd doesn't cause that.
This has been known ever since /cnd was introduced back in 2014. I'm honestly no longer sure whether it's intended or a bug. Absolutely intended behavior. /cnd's conversions are always reversible; one-way item compression must be forced via /cnd hand or /cnd all.