What happens if user B and user C are on a different computer than user A? I think this is an IE issue, and not a ColdBox issue.
Use Fiddler to confirm whether or not the browser is even hitting the server or not when it loads that page, or if it is using a local copy of the page.
Also, what cache headers are you sending back (if any)?
Try adding these into your layout for pages that you don’t wish browsers to cache locally on your users’s hard drive.