[Plugin: WPML Multilingual CMS] Translation disappears after editing original

Hello, I am using free WPML version on WP 3.1.1.
What I did:

• I wrote page in default language.
• I have translated it into secondary language.
• Then I have edited the content of default language. Pencil icon in page editor WPML box turned into “reload” arrow indicating that translation needs to be updated.
• I have switched to translation – and in the editor area, there was no text of the translation, just empty editor!

So I want to ask: Is this a bug? Or incompatibility problem (free WPML vs. WP 3.1.1)? In other words, will purchased commercial version fix that?

http://wordpress.org/extend/plugins/sitepress-multilingual-cms/