Aperture does not display projects. Only Albums.
This is documented in an Apple Support document, here:
http://support.apple.com/kb/HT1056
"Note that only albums (including Smart albums) are available, projects are not."
So, it's not a bug. . . it's a feature.
I agree this is silly, and frankly this was the main reason I did not migrate from iPhoto to Aperture, despite Aperture having a better organizational structure for my huge family photo library. I am hoping that the next version of Aperture will allow projects to be visible on the ATV2 or ATV3 just like iPhoto Events are visible. Because, as it stands, viewing photos on your ATV2 is more convenient with iPhoto than with Aperture (since iPhoto events are visible in a nice 2D grid of thumbnails, while Aperture projects are not).