The title says it all, but I will detail.
IF
-you are on ColdFusion 8
-and using the CFFTP tag with action=”listdir”
-and the remote FTP folder is on a UNIX system
THEN
–CFFTP will not list the files and folders having last modification date 29 February.

Why this happens?

Apparently, because of a bug in the FTP client used by ColdFusion. The FTP client is Apache Commons NET – FTPClient, and according to this article:

The Unix ftp server returns the date in the format “MMM d HH:mm”. No year info is supplied.
This caused problems, of course, since Feb 29 is not a valid day in the default year 1970.

When was this discovered?

According to this thread on Adobe Forum, it was first reported on 29 February 2008:

CFFTP from one Red Hat AS 4 server to another Red Hat AS 4 server is not retrieving files with modification dates of February 29 2008. The files simply don’t show up in the listing. They do show up in every other FTP and SFTP program I’ve tried, including command-line FTP from the system trying to CFFTP and from other systems on the network. It appears to only be affecting CFFTP TO a unix/linux system.

When was this bug fixed?

Today, 26 April 2012, the bug is still present. As one users points out:

It happened again in 2012!
On windows 2003 server with CF 8
Come on Adobe. Neglected this one for 4 years cost me 5 hours of work today.

One can argue that it is not a ColdFusion bug, it’s an Apache FTPClient bug. But when this bug is affecting the correct function of ColdFusion, then an action is necessary. Moreover, when behind ColdFusion is a company the size of Adobe, there’s really no excuse for not fixing it for more than 4 years.