Besides setting the deleted items retention time to 0 Is there is ever a circumstance when items deleted from the deleted items bucket in outlook would not show up in OWA or outlook?
I have a user (user 1) that has full access to another users (user 2) mailbox and this is made available in outlook.
User 1 deleted items from user 2 inbox and these items go to user 1 deleted items bucket.
User 1 then empties user 1 deleted items bucket.
User 1 then goes to recover deleted items option for user 1 and only see some of user 2 items that were deleted.