User Agent: Mozilla/5.0 (Windows NT 6.0; rv:19.0) Gecko/20100101 Firefox/19.0 Build ID: 20130307023931 Steps to reproduce: Opened an IMAP folder (which is configured for offline use). Noticed that some emails have current wallclock time in Date field instead of their real Date (checked in mail headers as shown by CTRL-U). Opened folder preferences, hit Repair Folder button. Actual results: ALL emails are now displayed with Date = current wallclock time, except for those which have actual Date: header equal to some time today -- in this case, they show real time. Expected results: Older emails should show their real date, as specified in email Date: header, not the wallclock time of when they have been downloaded by Thunderbird.
The same happens for us, but only on some accounts. On another client it works fine, so the issue is not with the server.
Ihis doesn't have enough info to go anywhere.