Was this bug ever resolved? This sounds a lot like the bug i am having here:
https://www.mobileread.com/forums/sho...d.php?t=120474 Kovid, if i follow your advice and do "show info" in Calibre's ebook viewer it shows the UTC time whereas viewing the Calibre metadata shows the local time. It seems the MOBI is embedded with the incorrect time, which causes the Kindle to see the file as published on the wrong date.