I would recommend submitting this problem at issues.ez.no. If you haven't missed something, looks very interesting/scary... Also, it would be good to know with what version of eZ Publish this has happened.
It is with eZPublish 4.0. But, I can not reproduce the problem anymore. I tried to add an attribute, and it works (as it supposed to do) in every languages. The real question is "Why and how this thing is happened?" I supposed it was when I was adding the attribute. and after this, I have to admit that I did not verified at once every languages, only english (and it was OK).
Fabrice, The only thing that comes to my mind that you might have done wrong is checking an attribute as non-translatable. In such case, it would not appear when performing translation (provided that you were talking about multi-language nodes and not separate one-language documents...).
