Last modified: 2014-04-15 21:41:47 UTC
The (visual)edit button in a diff (such as http://it.wikipedia.org/w/index.php?title=Kawakami_Gensai&diff=20609681&oldid=18301858) makes you edit the last version (in the example above the edit button gives the link http://it.wikipedia.org/wiki/Kawakami_Gensai?veaction=edit), whereas clicking on edit source makes you edit the old version (the newest of the two compared versions).
Confirming this - http://it.wikipedia.org/w/index.php?title=Salamandrina_terdigitata&diff=60451620&oldid=57566108 .
This looks to be possibly the same issue as bug 51364
As far as I can tell the edit source and edit links point to the same oldid. Is this bug still valid?
This was fixed some time ago, it appears.