I have just done a clean install of the latest Thunderbird on Mac, and connected via IMAP to a pre-existing (although admittedly very large) mailbox. My problem is that every single message apart from the ones received today shows a date that is wrong by nearly 600 years for both the Date and Received columns: e.g. from the year 1403 instead of the year 2024. I am attaching two screenshots, the first shows a message received today that shows correctly (I am UTC+1, so 00:29 is correct). The second shows a message received an hour earlier where the date and received columns show 13/02/1403 at 23:30 instead of the correct value that appears in the Date header of the message of 02/05/2024 (all dates in DD/MM/YYYY because of my locale). Does anybody know what is causing this? When I try connecting with other IMAP mail clients such as Outlook/Mac or K9/Andoid I do not see any problem with the displayed dates.