I'm 65 hours into a triple crown run and I was hoping to get the steam achievement...
Anyway I lost two items. Definitely had them after killing the guy in Blood Sands, then I headed straight to Elmshore to finish the Berath quest. I started fighting the Will-o-wisps when I noticed that Lenas Er (the primary for my Cipher) was unequipped. Also, the PC's off hand dagger (something Accuracy +3) went missing at the same time.
There aren't many Superb weapons in the game, and losing one is a bummer.
I tried uploading the savegame file, but it's 4Mb which is beyond the 507k limit.