Nowiki users noticed that their project's edit counter was showing (via WikiApiary - https://wikiapiary.com/wiki/Wikipedia_(no)#chart1) a massive (>1m) edit drop. This should be literally impossible, since it's working from Special:Statistics, which simply counts the number of rows in the revision and archive tables. Investigation found no discrepancy between the current (1m< peak) data and the database, and no discrepancy between the current data and the most recent dumps, which leads to the question of how and why Special:Statistics overcounted.
updateArticleCount.php or equivalent sitestats refresh was run on some wikis around 2014-11-29, correcting some mistakes in the on-wiki statistics (cf. https://bugzilla.wikimedia.org/show_bug.cgi?id=10834 ). We don't yet know what triggered the update.
Copy/pasting report by user:Jeblad on Meta:
"It seems like 29. nov or shortly before there was a drop in number of articles at nowiki and fiwiki. For nowiki it was from about 435k to 401k articles. If this drop is just a change in how the databases counts the articles then it doesn't matter much, but if this is a real issue then it should be fixed. This is a much to large drop to be neglected. [...] Compare wikiapiary:Wikipedia (no)#chart1 with wikiapiary:Wikipedia (da)#chart1 or wikiapiary:Wikipedia (fi)#chart1.