while I am working on Netflix command as discussed here http://voxcommando.com/forum/index.php?topic=1808.msg15754#msg15754
I had my Netflix groups with a prefix override in their setting. however I noticed that the prefix stop responding after group rebuild ...

am not sure if it is a bug or how to verify if it is one or how to capture it in a log ...

Thanks for the heads up Haaadddooood!  I think I have a working fix.  It will be in the next release.