InstaDMG: Volume failed to eject error after rolling in FrontRowUpdate 2.1.2

Took me a few builds to narrow this down, but after adding FrontRowUpdate2.1.2.pkg to the build order, I get this during the build: [code]Volume failed to eject asr: successfully scanned image "/Volumes/Spare/InstaDMG_1.3b/Instadmg/ASR_Output/08-03-03.dmg" [/code] Even after InstaDMG completes, I still can't eject OS-Build-08-03-03. It's reported as in-use. Any suggestions about what might be causing this? Dumping the CLI doesn't clear the problem. Is the build likely still usable?