Since the switch to package-level data in the model building only packages (rather than an image with packages) doesn't work. The fix for this would be to include the corresponding PN for each package in the model and on package only build selection pass a uniquified list of PN's to the buildTargets command.
http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=a17e6c4a2ebb3af6f8c7201b946304fd06602c24
Fixed