The actual messages have the right date and time in the headers, but are being displayed in Outlook and OWA with...
the import date. Is there a way to "re-index" a user's mailbox after the import?
To understand exactly what's happening, I'd suggest using the Field Chooser in Outlook to display more of the Date/Time fields, specifically Received, Sent and Modified, to determine exactly which fields are showing correctly and which aren't. You can then use Outlook views to show the appropriate field as a stop-gap measure.
Do you have comments on this Ask the Expert Q&A? Let us know.