With VoiceOver, you cannot select text across page breaks. Trying to do so simply de-selects everything on the first of the two pages and does not extend the selection to the next page. You must select up to the page break, paste the text somewhere else, then select the rest of the text after the break and do the same thing.
Bug First Encountered
How often the bug occurs
According to a seasoned Pages user who posted this morning on the MacVisionaires email list, this bug has been squashed in the latest update of Pages for OS X.