[mkgtu]

As of about 3 months later this issue described below has been fixed. Several people reported the "fix" late in December. I checked myself and can confirm that everything is working as it should for me also. SEE MY POST FOR DECEMBER 25, 2020.
AND MERRY CHRISTMAS!

This is a very recent issue. Whether using the "Send to Kindle" app or sending by email, the software doesn't retrieve the author name from the metadata as displayed in the filename and so the "author" shown in Kindle will only be your own name or your email address, not the book's real author! You can, of course, manually type in an author name in the "Send to Kindle" app (on computer or mobile device) for just a single book (but not for multiple/batch uploads). So you can effectively only upload one book/doc at a time. But you can't add an author name at all if sending a file to your Kindle via email. So if you want an author name, you cannot presently use email!

I don't know how clear the following is, but I sent
the detailed message below to Amazon via "chat". The chat person said she would file a report to tech on my behalf. Where that ends up, who knows? Perhaps others have noticed this issue?

Message to Amazon:
"Whether using the Send to Kindle app or email, the service does not seem to be reading the author info from the metadata. If you select a book and right click to use Send to Kindle on PC, in the Title line the author shows after the title, separated by a hyphen: "Book ABC - John Doe". You can leave the actual author line blank. The sending service reads the author from the title line. That's the way it's worked for years. BUT in the last few weeks, unless you put the author name in the actual "author" line of the app, the service uses MY OWN name as author, and my name is listed in the author column in the cloud and on all devices. (and though the author name is included after the hyphen in the title line, only the title is transferred to the devices and the cloud - it doesn't show in the title itself, it's just ignored) However. if you put the author in the author line, then it works correctly, and the author name shows up where it belongs on your devices.

"Of course, this means you can NEVER send multiple books anymore via "Send to Kindle" app because it won't pick up all the individual author names from the metadata. You'd need to send things one at a time and add the author name manually. The same is happening with sending personal docs or books via email. The author comes out on the device as the email address you used to send the files. Which means if you want the author to be correct on the Kindles and in the cloud storage, you can't use email at all because there's no way to add an author name other than via the metadata in the file itself, which the Kindle document service is not currently able to read.

"The docs/books I'm sending are all in .mobi format. Some were converted from .epub in Calibre. Some were already in DRM-free mobi format from other sources. So I doubt there is anything wrong with the metadata itself, given the various sources of the files."