Rebuild_index generating incomplete index?

I added acts_as_ferret to a project with ~40k products, but running
rebuild_index is not adding all of those to the ferret index
(Product.rebuild_index.size returns 26632).

Any ideas?

Thanks

Fixed, I think I found a bug in the plugin. See
http://projects.jkraemer.net/acts_as_ferret/ticket/212