Don't know how to name it, see my image:
On April 23rd 2014, automatic process changed all links pointing to questions in http://meta.stackoverflow.com to point on http://meta.stackexchange.com instead. There is redirection in place of course, but when possible it's better to avoid the extra request.
However, there was a bug in the initial process:
Yes, this was a bug in the migration code.
A fix migration is being rolled out (using the previous revision as the basis of the change).
While this clearly explains revisions #3 and #4 not totally sure why the additional revision but I'm pretty sure it was the new migration fix running again to make sure everything is fixed.
Anyhow, no bug and no harm done as those edits didn't bump the questions and there was even no risk of making the questions Community Wiki due to recent change. :)