The two following files, 74413 and 74414 (Hana Yori Dango 19 and 20 by Anime_Fin), when auto-renamed by the client, are changed from OGM files to AVI files.
I think it already happened once to me, with another title, but I don't remember which one.
It may be because I already had the Fumei files for the same episodes (40061 and 40066), which are legit AVI files.
The strange thing is that files 74115 and 74116, which are eps 17 and 18 by Anime_fin) were released at the same time, but don't exhibit the same behaviour.
Edit : looks like the ed2k link in Anidb is the culprit, having been incorrectly entered as an AVI file. There is currently a Creq on these files, so I can't request a modif.
This is not a client bug, as far as I can tell, so this topic may be closed, or moved to the "db change request" part of the forum.