After I added a release with a wrong title, I edited the release title and checked the box to change the title of the release group at the same time. This action has generated these two edits: <http://musicbrainz.org/edit/32583397> (release group title) and <http://musicbrainz.org/edit/32583398> (release title).

The problem is that I can see the correct title in the page of the release group <http://musicbrainz.org/release-group/feaf53b5-03ea-408f-bdf9-96b1da5e8334>, but the page dedicated to the release <http://musicbrainz.org/release/9064e1b0-1062-457d-aa88-9bdf4b9f4bed> still shows the old, wrong title. The data fetched by Picard is also out of date.

On IRC, chirlu said that this issue is probably due to a race condition between the edits and the cache system. This race should be fixed or the cache should be forcefully invalidated every few hours, so to make sure that these small errors will eventually be resolved.