From the forums… Lethal Bug Report
"시체전문가212 posts
12h
Lethal Bug Report (All items in a shared item stash disappear)
Bug Acting Conditions
Put items in a shared item stash as a ladder extension character
Put items in a item stash as a ladder original character
When you check the shared item stash with the ladder extension character, all items evaporate"
This is probably exactly what happened to me, because i wanted to clean up a (classic) char on my alt account and moved it to my main account (the sorc)…
Check this link too Diablo II: Resurrected Patch 2.5.2 - Release Notes (11/1) - General Discussion - Diablo 2 Resurrected Forums (blizzard.com)
Make sure u send a ticket to blizz!!!