It looks like the page_id is corrupted somehow, from data on July 9 and July 10. Does this come from the replication tool, or the replay tool?
http://tools.wikimedia.de/~interiot/cgi-bin/queries/tmp/en_munged_pageid
In the cases I've seen so far, rev_id and user_id seems to be correct, but page_id sometimes is not.
-Dave