Regularly finding episodes missing from the listing that show up for other subscribers.
While this has happened in the past (and I see other users have reported this and been given eroneous solutions), right now, I'm looking at my neighbors On Demand listing for AMC showing episode 307 of The Killing available, yet it does not appear on the listing (under regular or high def) on any of our 4 boxes (3 of which are from different manufacturers). The show aired 72 hours ago.
This is definitely not a content provider issue or issue of Cox not having it yet, as it's clearly available to other subscribers. The boxes have been power cycled.