Disclaimer: I am a Comcast employee, especifically in the department responsible for ingesting the metadata that powers your channel guide.
Channel listings are at the discretion of the providers. For example, CNN could decide to switch their programming 30mins before the show actually aired. That update needs to flow down to us and we have to be able to update listings for millions of people (esp for national streams) to reflect said update. From experience, I can tell you that a 30min heads up is not enough for all those updates to trickle down to our customers. So the short is, it is likely we did not receive the update in a timely fashion that would have allowed for the changes to take effect before the program started. In some cases, the providers do not even bother sending the updated programming schedule, so this really has nothing to do with the box, but everything to do with the data providers and when they decide to make changes to their programming, update clients downstream. If the update is finally processed after the program has ended, I do not think there's much that can be done as of today.
Information may be good, but anyone can come along and state they are an employee and then end up stealing user information.