@superplinio and grizedale: Nighttime ruminations produced another scenario that makes more sense than the one above. If your Sony reader things it is in a timezone different from the one for your computer, then calibre will set the date of the book incorrectly in the Sony db. Result: the sony will 'repair' the entry, getting the information from the epub. This will change the author back to whatever it is in the book, and in passing correct the date. The next time you send a book, calibre will put the author back to author_sort, but without touching the date, so the change sticks this time.
So, my question: do you/have you ever used the Sony Reader SW to talk to your reader? If so, could it be that you last used the Reader SW in a different timezone, or back before the change to summer time? If so, then connecting Sony's SW to your device (doing nothing else) should fix the problem, at least until the winter time shift. Note that I never use Sony's SW, so I cannot say whether allowing it to connect will have other consequences, such as collection modification.
If you never intend to use Sony's SW again, then in theory doing a *hard* reset will fix the problem. A hard reset restores the reader to factory defaults, including erasing all content and device authorization. The factory-provided books will be erased and not restored.
The procedure for the 300 can be found at
http://support.sony-europe.com/compu...n_GB&m=PRS-300. I tried it up to the point where it asked if I was certain. Instructions for the PRS-600 are at this site:
http://support.sony-europe.com/compu...n_GB&m=PRS-600