ivanovitch,
You meant to post this in the Pages '08 forum.
After I read your post, I tried to duplicate the problem you described and, unfortunatley, I was successful. I put some text in a table, went back and made changes and ... nothing. Until I inserted a text box and started typing in it -- then Pages mistakenly thought everything I was typing was a change, and shaded it in blue. Very weird behavior.
So Pages won't track changes in a table, yet will report the next occurrence of typing as a change, no matter where it occurs (text layer, text box, object).
I'd suggest sending
some feedback to the Pages team.
-Dennis