[mgmueller]

First of all, let me say I'm a huge fan of Kindle.
I've got 5 of them and all work great.
And of course I have the Kindle app on various platforms as well.
Twice within a week, something strange has happened:
I have about 600 Kindle books in the Kindle app on Sony Tablet S. And on half a dozen other units (some books only can be downloaded to 4 units, so I have them only on Sony Tablet S and 3 others).
Those ca. 600 books all have been bought from Amazon and not been modified in any way. Directly downloaded them, no sideloading.
I've read a book in the evening.
Next day I wanted to continue that book.
I've been offline both times (I've got the Sony Tablet S WiFi-only model and both times there was no WiFi around).
The Kindle app did show my whole library and then started to delete all my books. I didn't see any actual deleting, but I saw the counter stating the number of my books in my library declining to "0".
I've restarted the app, but the books really had been deleted.
I've redownloaded all books again (quite a pain in the %/&(, even via fast WLAN).
It had been working for a few days, but yesterday the very same has happened.
This time I didn't wait for the counter to decline to "0". I've exited the app and restarted it. Still: Again all books have been deleted. Not just from the app, but physically from the Tablet.
I've checked the registration in the app: Still valid and correct.
I've checked my Amazon account, Sony Tablet S still is there.
I'm just downloading the books again, no problems so far.

The only theory I've got: If the app is under the impression, the account wouldn't be valid anymore, it might make sense to delete the books. But wouldn't there be some kind of warning signal? Something as "Do you really want to proceed with your new account? Warning: Your entire library will be deleted then.".
So this theory doesn't seem very plausible. But it's the only idea I can come up with.
Why else should the app delete my books?

Any ideas? Did anyone experience this as well?