I haven’t confirmed this myself, but I believe Scott when he says that the latest version of RSS Bandit changed some of the keyboard settings. In particular he states that to mark a post as read changed from CTRL+M to CTRL+Q.
The reason I didn’t notice is that I am using customized keyboard settings. It isn’t too hard if you use my (unsupported) keyboard setting tool for RSS Bandit.
I wrote up a two-part article about how keyboard settings are implemented, but the only part you really need is part 2 in which I describe a quick and dirty tool for modifying keyboard settings.
This tool simply provides a GUI for modifying the ShortcutSettings.xml file (an embedded resource file available with the source code) and making a copy of it to the following directory: C:\Documents and Settings\YOUR_USER_NAME\Application Data\RssBandit\ShortcutSettings.xml. Once there, new installations shouldn’t override your custom keyboard settings.