Maybe i'm missing something but take this example:
Page "Westplex" redirects to "St._Charles_County,_Missouri": https://quarry.wmflabs.org/query/43707
It apparently does so since 2018: https://en.wikipedia.org/w/index.php?title=Westplex&type=revision&diff=828554258&oldid=827301936
Yet in pagelinks: https://quarry.wmflabs.org/query/43706
The redirect page contains some navboxes, the links seem to come from those...
On a related note: the redirect table is said to only track redirects that have been changed after 2007. Without deeper knowledge of the subject, I wouldn't necessarily assume that old redirects on Wikipedia have been touched since then. That's why I opted to reconstruct them from the pagelinks+page tables instead. Someone on IRC said they think every page will have experienced an automated update of some sort since then, prompting them to be tracked.
Do you know more about this? Can I rely on the redirect table tracking all (relevant) redirects the way the pagelinks table does?
This is news for me. But we can quickly check if all redirects have an entry:
SELECT page.* FROM page
LEFT JOIN redirect ON rd_from = page_id
WHERE page_is_redirect = 1 AND rd_title IS NULL
