ubuntu one "unpublishes" previously published files ?

Twice in the last few days, the files that were formerly "public" on my ubuntu-one free account, got unpublished (all of them!). They are still synchronized but can't be accessed from the web with the "weblink" URL.
 Since these files should be accessible from my personal website, my site appeared "broken".
I had to go through all my files in my Ubuntu-one folder in order to re-publish all of them!
I can't say where the problem comes from: Is it on the ubuntu-one server side or on "my" side (that is, an ubuntu 11.04 (natty)bug)? One thing is certain: I didn't "un-published" them by myself...
I use Nautilus as a file browser and to publish the files.