Previously, when deciding which revisions to import, Special:Import ignored any revisions in the source wiki/file that had exactly the same timestamp and username, but slightly different text. This was handy for the Nostalgia Wikipedia, a read-only copy of the English Wikipedia database from 20 December 2001 that, for various reasons, has slightly different text to the current Wikipedia database. Now Special:Import imports them anyway; this happened at the Fernando Pessoa and Abdul Hamid II articles on the English Wikipedia. The system was working fine yesterday, when I imported an edit from the Nostalgia Wikipedia to User:User:Sjn28.
Sure. Here's a permalink to the logs of the two bad imports:
In both cases, Special:Import should've only imported one revision. This is how it worked until today (UTC).