When both Vintage mode and the Zen Coding package are installed/enabled, there is a key-binding conflict with the colon (':').
Type ":" (the Vim symbol to preface a command) while the cursor is in the first space of a line. A colon is printed into the file instead of being passed to the vim command line.
So far, I've only noticed this behavior in CSS files.
Let me know if there's any work around! Thanks,