Wikimedia Bugzilla is closed!

On nlwiki, the wanted templates special page [1] shows
Template:Template_call1 as 'most wanted', with 76 pages using it.
However, of those pages, 75 are from page_id's that no longer exist in
the page table. This happens for a larger number of templates: a scan
of the database [2] on the toolserver reveals that Template:Echo,
which does exists, has 1866 entries from non-existing pages in the
templatelinks table.

This problem is not restricted to nlwiki (the German query [3] has
template:Bausteindesign4 with over 12000 orphan entries), nor to the
pagelinks table (a query on the pagelinks table [4] yields several
results).

What causes this effect, and is it possible to let the software
trigger a cleanup on certain pages when they become annoying (i.e.
when they appear on the wanted templates special page)?

Best regards,
-- valhallasw

[1] http://nl.wikipedia.org/wiki/Speciaal:GevraagdeSjablonen?uselang=en
[2] http://toolserver.org/~valhallasw/tl_nl_snip.txt
[3] http://toolserver.org/~valhallasw/tl_de_snip.txt
[4] http://toolserver.org/~valhallasw/pl_nl_snip.txt
(please note the database readouts have been | head -n 100'ed. They
are in the same encoding as the databases itself, which means utf-8
for newer and latin-1 for older entries)