Next go to the "Hall of fame" (don't knwo the exact name I'v a german client - it the thing at SI:7 where you get PvP things).
It's the Champion's Hall in the english client, but either way it's the instance portal :)
When inside - check again for the items.
Ah, ok, I see, the items in the bank bags disappear but the main bank inventory is still there. Can't believe I hadn't noticed that before. Interestingly, other characters bank inventory appears to be intact, only the current one gets wiped.
I'll see if I can track down whether it's a problem in Sanity2 itself or in the item cache.
EDIT: I can reproduce the problem without Sanity2 loaded, so it looks like something in SanityItemCache.