I have a bilingual site (English/Serbian) with a translateable taxonomy. The problem appears when entering new nodes - there are four taxonomy categories and, when creating a new node, they appear in English or Serbian depending on the administator's current language. To help you understand better, here's what it looks like: let's say the site administrator has selected the English version of the site. He creates a new node, selects the language for the node to be Serbian, but the taxonomy categories (which are checkboxes) are in English - because Drupal remembers that the administrator is on the EN version. If the administrator saves the node (which is in Serbian, but because of this problem has an English taxonomy) and then switches to Serbian and edits the node, all the taxonomy check boxes will be in Serbian - but unselected. And vice-versa.
I hope there are some settings for this.