Screenshot on June 28, 2010
When the <pagelist> tag is used in an Index: page, it normally produces a list of pages. But sometimes, without any apparent reason or cause, the Index: page instead displays the <pagelist> tag (as if it had been enclosed in a <nowiki> tag). When this happens, any transcluded pages (that use the <pages> tag) lose their tab linking to the source document (the Index: page).
A work-around is to save a null edit (adding or removing some whitespace) of the Index page.
This bug was observed on June 27, 2010, on http://sv.wikisource.org/wiki/Index%3aÖstgötars_minne.djvu
and on June 28, 2010, on http://sv.wikisource.org/wiki/Index%3aEskimålif.djvu