Commons had problems with server lag. This meant that it took longer time for files to turn up in categories. 
Changes this week
The new version of MediaWiki will be on test wikis and MediaWiki.org from 24 May. It will be on non-Wikipedia wikis and some Wikipedias from 25 May. It will be on all wikis from 26 May (calendar).
You can join the next meeting with the VisualEditor team. During the meeting, you can tell developers which bugs you think are the most important. The meeting will be on May 24 at 19:00 (UTC). See how to join.
All HTTP access to Wikimedia sites and APIs will stop working. Some bots still use HTTP. They will need to use HTTPS instead. This will happen on June 12.