I recently re-installed Oblivion and with the Shivering Isles content. When I started the game, I was surprised to see I didn't have the 1.1.5 . . . patch but one I had never seen, 1.2 ... I figured this patch came over the Internet when Bethesda saw I had the game installed (just recently got hi-speed at my apartment in Thailand--and yes, my game is a "real" game).
Now, I am at the 150 hour mark and like the original game, I am mysteriously losing items. Any ideas?

1.2 (1.2.0214) is outdated. you need 1.2.0416

http://www.elderscrolls.com/downloads/updates_patches.htm

I remeber that bug

I caught it with the SI expansion

SI just adds to many items for the original OBL database to keep track of, so I was losing enchanted items

It went away with the GOTY edition

FormID bug. You'll need the 1.2.0416 patch.